Fluky's, the venerable Chicago hot dog stand, makes their own brand of sport peppers (aka, "serrano peppers") -- but I didn't think they were worth the price, when I could get simple La Preferida Sport Peppers for cheaper, and which should be easy to locate wherever you live, if you're inclined to make your own Chicago-style hot dogs.
And there you go! Nummers! Easy to do. And so yummy! I think celery salt is really the key, since the remaining ingredients are self-evident.