When filling corn tortillas in the preparation of enchiladas, is there a way to prevent them from cracking and splitting while rolling the individual enchiladas? If there is a way, I suspect it must involve heating. Should they be heated dry, perhaps wrapped in foil and placed in the oven? Or is steam necessary? Is there another way which doesn’t involve heat?
The traditional way is to fry them for a few seconds in very hot oil, then dip them into the enchilada sauce before filling and rolling.
My family has always done it by wrapping the corn tortillas in foil and sticking them in the oven for a few minutes. We still get the occasional crack, but a little sauce & cheese “caulk” works wonders! 
If there is a way to do this without heat, that’d be great; but usually the oven is hot anyway (for the impending enchiladas), so it’s a time saver as it is.
Or you could use the Northern New Mexico “stacked not rolled method”. The modern shortcut for this is to put corn tortillas and a daunting quantity of olive oil in a ziploc bag and microwave in 25-45 second intervals, wiggling the bag around carefully at each interval to work the oil into all the tortillas. Then, assemble a tray of enchiladas as if you were making lasagna: layer of sauce, layer of tortillas, layer of sauce, layer of cheese, layer of “filling”, tortillas, sauce, cheeses, filling – ending with the tortillas, sauce, cheeses sequence.
[Firesign]
“Corn! Now we can make tortillas!”
“We’ve been waiting hundreds of years for this.”
[/Firesign]
Couple ways that usually work for me.
A light spritz of olive oil on one side of the tortilla as you stack them.Rub them gently together to coat the other side,then nuke briefly with a damp towel covering.
If your filling tends to separate,dip the tortillas in the liquid portion until they get pliable.Careful;too long and they mush.
You do have to heat them to make them pliable. We usually heat up a little of the enchie sauce in a skillet and dip each tortilla for a few seconds before rolling.
I heat them dry in a cast iron skillet, myself, until they puff a bit. Then dip them in the enchilada sauce. Works really well for me.
This is how I’ve always done it. It’s how I prepare corn tortillas for tacos, too. I slide 'em into the hot oil, let 'em fry just long enough to puff up, then side 'em back out. I put the cooked ones on a plate with a paper napkin between each one. If you just stack 'em, they stick together in a block.
Now I’m all hungry for tacos and enchiladas.
This way works very well for me, even though I’m in North Texas…and I thought that I’d invented this system. I don’t even bother with the olive oil, or heating the tortillas. I just layer everything in a pan. My husband and daughter prefer flour tortillas, while I prefer corn. Oh, and I usually throw in some refried beans with the meat.
“I just invented tacos!”
Another vote for the Other Traditional Method: stacking. (Inherited via Albuquerque.)
Yep, the OTS works for me too. Dip them in hot oil (lard ;)), then sauce.
If you’re going to stack them (Sonora style), let them crisp a little. I really like corn tortillas, so I usually use this method. I have a dish the same size as corn tortillas.
There’s a place here in Berkeley (Picante) where I can get fresh, house made corn tortillas.
Crap! Now I gotta go shopping.
I’m also from the “heat them in a dry skillet” school of thought.
GT
I just put them in a plastic bag with a small amount of water and then microwave. No need to fry them or use oil.
Frying them in oil is a good thing.
My current wife daubs them with a water-soaked paper towel. I prefer to schpritz them with a food-grade water bottle. Get 'em shiny on one side and they’ll usually work out.
Get yourself a can of La Victoria red enchilada sauce and follow the directions on the back. Millions of Mexicans do just that. You can omit the beef and increase the cheese and onion.
CANNED enchilada sauce? None of my Mexican friends do “just that,” including one friend who taught me his sainted grandmother’s recipe. She didn’t speak more than one word of English.
I am going to have to call shenanigans here, and ask which millions of Mexicans you are referring to.
With respect, your experience may differ. According to TIME in Mexico the average weekly meal expenditure is $190, a portion of which appears to be canned and processed food. Just because it’s canned doesn’t mean it’s not good. It just means the cook didn’t have a few hours to burn.