Starting on one long edge, use a sharp knife to butterfly the flank steak, cutting it open parallel to the cutting board, so it can open like a book with two thin layers. Stretch the flank steak out and cover with plastic wrap. Use a meat tenderizer
(or rolling pin) to pound the thickest sections creating one even thin piece of flank steak, double the length of the original. Remove the plastic and sprinkle Old El Paso Fajita Seasoning over both sides of the steak. Then cut the flank steak into twelve segments, 2.5 X 5 inches long.