Preheat oven to 350°. Lightly coat frying pan with oil (optional), and heat on stove top at medium-high. Slice steaks into 3/4 inch strips and set in pan. Add black pepper, salt, and crushed red pepper.

Dice green pepper and onion, add to pan. Cover and let fry until steak is thoroughly cooked, stirring occasionally.

Fill tortilla shells with mixture from pan and add cheese generously. Coat pan with non-stick spray. Lay filled shells on pan and place in oven until torillas are golden brown and slightly crispy.