Put the onion, beef, olive oil and green pepper in a pan ultil the beef is no longer pink and add Del Pico relish. When ready, then drain off the grease.
Wisk together the mayo and sriracha and set aside.
Place the bottoms of 12 small dinner rolls in a greased 9x13” pan and spread an even amount of ketcup on top of them, followed by the cooked ground beef and American cheese slices. Put the spicy mayo on the dinner roll tops and place on top of the cheese.
Bake at 400 F for 5-10 minutes and you are ready to eat!