I have had a huge success with coating tatertots with a little oil and baking them. Deep fried goodness with a lot less oil. That’s the hack that Big Tots™ doesn’t want you to know about but not the one this thread is about. Could the same thing work on taco shells? Get/Make some corn tortillas, brush on some vegetable oil, place them in a taco-shell-shaper, and cook them in the oven and get that great crispy shell without deep/shallow fat-frying them?
Back when I could eat them, I’ve found the best way of making tater tots/crispy crowns was on the grill outside in a “dutch oven” of sorts fashioned in a pouch made of aluminum foil. Just puncture some holes in one side.
They were moist and potato-ey on the inside, crispy outside, and no oven clean-up needed. Crumple up the foil and chuck it away when you’re done.
Use corn oil. It should work but you’ll have to work out a good temperature and timing. I don’t like crispy taco shells so I’ll pan fry them with minimal oil and just fold them over when hot. They’ll remain a little pliable that way. I think you’ll want the oven hotter than 350°F so they’ll crisp up quickly.
Depending on the food, you might not even need the thin coating of oil. And even if you do, a spritz of cooking spray is usually enough.
A bunch probably depends on the corn tortilla’s composition. One of the reasons (for me at least) that I can do fine with minimal oil for tater tots in the air fryer is that the damn things are full of oil by default - often the same for other pre-formed potato products.
So heavy, made from scratch with RealLard 
corn totillas may do well as-is in a mold in a very hot oven. Skimpier options will probably benefit from a Misto spray with corn or a neutral oil. But I’m more an open faced or simply folded taco person like @TriPolar - so I’m giving an educated guess towards baking on the hotter end for a hot-and-fast shaping method.
I think oil is the key, and getting the right amount may take some experimentation. When I do tater tots in the toaster oven I don’t use any oil on the potatoes. I’ll put some on the roasting tray just to keep things from sticking, but they aren’t being cooked in that oil, just cooked on that oil.
In the past I’ve done corn tortillas in the toaster oven to make tostadas, and in my experience oiling the tortillas is necessary. With no oil they first get pliable, but they seem to dry out and get tough, instead of getting crunchy. I like to see the oil bubbling on the tortilla, so they’re definitely frying, but just in a thin coat of oil.
So I say experiment with making tostadas, and once you have the oil levels correct, then try shaping them before frying.
I doubt that oil in the tots matters much at all: In conventional frying, the role of the oil is just to ensure thorough contact between the food and the heat. Properly-fried food retains almost none of the oil, and when your heating is all radiant and/or air convection, the oil wouldn’t make a difference for coupling.
Do you have an air fryer? (I got one as a gift, but haven’t used it - I will someday, I promise. I really will.)
If you go to YouTube and search “air fryer taco shell”, you will get with videos like this one. I’m not sure, but I think this is the cool air fryer lady recommended recently in a thread. Probably worth a look, if you have an air fryer.
Nope. And I’ll probably never get one. Everything I’ve heard is it doesn’t replicate that true deep-fat flavor.
I’d say for purchased, pre-breaded, oily fried food, it seriously gets to 80-90% But for any sort of homemade fried food, probably only 60-70% even with a serious coating of aerosolized fat.
So if flavor / speed of cooking is all you’re about, yeah, a true deep fry is where it’s out. For me though, the vastly reduced mess, cost of oil, and oil replacement / disposal is worth it for a lot of things. And even when not trying to heat breaded food, it does a great job as a mini convection oven, which is useful.
But, that means it works -just- like you described cooking your tater tots in the OP - add a little surface oil and cook hot and fast. So it’s certainly a natural question depending on what fried food you might want to cook. The Kirkland Panko fried shrimp or tempura do really well, as do various seasoned fries. But with airflow, I’d probably avoid fried taco shells.
Not exactly what the OP describes, but I’m always looking for faster and better ways to cook tater tots and other frozen potato products. So instead of baking for 25 minutes (we rarely fry, due to the mess), I’ll microwave frozen tots for a minute or two, until they’re closer to toom temperature. Then I’ll either broil them or finish baking for about ten minutes in a hot oven. The taste is fine, but the microwave really reduces the baking time.
We use corn oil spray for things like this.
When I worked cooking at a restaurant, people with cardiac concerns would order their fish “dry”, that is without oil. A cook showed me how to dip my fingertips into oil, then carefully massage the fish. After broiling there’d be no sign of oil, but the filet would be moist.
Related concept: with a little googling you can find recipes for oven bake falafels and onion bhajis. No, they’re not quite the same (or as good) as the deep fried version, but needs must and all that.
j