Cook steaks in pan coated with nonstick spray until no longer pink, chopping with utensil as you cook; set aside on plate covered with paper towels. Sauté onion and peppers in oil until slightly tender. Return steaks to pan along with fajita sauce. Stir to mix. Cook just long enough to heat steaks and vegetables thoroughly.
Place mixture in warmed tortilla, fold in bottom and sides of tortilla. Serve immediately. Serve with refried beans and Spanish rice.