I have to second portillo’s in Chicago (well the Burbs anyway) a hotdog must have 2 things to be eatable: steamed - nothing must touch direct heat. The dog, the bun, everything. And 2 - it must and I can’t stress this enough must NOT NOT NOT have any kind of tomato sauce on it. No ketchup no nothing!
Damn it folks it just plain wrong.
I visited Chicago last year – what was marketed as the “Chicago hot dog” was just as you describe, but with fresh red tomato wedges, not green pickled.
Flo’s Hot Dogs, Rte. 1, Cape Neddick ME.
The rest of ya can all shut up now. 
Portillo’s - Thirded.
Just returned from our daughters wedding, held in Hoffman Estates outside of Chicago. The grooms family brought our southern family there to eat on one of our vacation days and it was so good that we went back again before the week was out! Good stuff - which is mighty high praise coming from an area with some of the best food in the country
Seconded! All other’s are not entitled to use the words “Hot Dog”.
Explain to an alien why a Portillo Dog is anything more than a typical good Chicago Dog, available all over Chicago.