Heat 1 tbsp. of oil in large skillet over medium-high heat. Fry huarache in oil until it becomes golden brown, repeat process for remaining huaraches. Season steak with desired salt and pepper and fry with onion slices for 2 to 5 minutes per side. Remove the steaks and chop into small pieces. Spread refried beans on each huarache and chopped steak bits. Serve each huarache with minced lettuce, sour cream, cotija cheese, and green salsa.