Slice meat with food processor as thin as possible. Cut onion into thin slices.
Heat oil in large skillet on medium-high. Add meat and onion and season immediately. Feel free to play with your spices. I like to use a seasoned salt and pepper like Krazy Jane's for this dish.
Cook meat until done, then taste meat and add more spices as needed. Remove from heat.
Meanwhile slice rolls partially open and put two slices of provolone on each. Toast in oven on 425 degrees until cheese is melted.
Pile meat and onions onto rolls and top with pepperoncini. Serve hot.
TO MAKE AHEAD: Undercook meat slightly and transfer to a crockpot on warm setting, not low or medium as you don't want the meat to overcook. Make the buns as directed and arrange on a platter nest the crockpot. It's okay if the buns aren't warm since the meat will reheat them.