Prepare Lime Marinade (see below); set aside.
Lay the skirt steak on a cutting board and remove the outer membrane (grab the membrane with one hand and slide the knife beneath it, cutting as you go). Using a sharp paring knife, make a number of slits in the meat, cutting both with and against the grain of the meat (this cuts the muscle fiber and reduces any toughness.)
In a large plastic bag with the Lime Marinade, add skirt steak; reseal and marinate in the refrigerator at least 1 hour or overnight, turning steak occasionally.
Remove steak from refrigerator and bring to room temperature before cooking.
Drain steaks, reserving marinade. Place steaks on the hot grill and spoon some of the reserved marinade over the steak. Close barbecue lid, open any vents, and cook 3 to 5 minutes for medium-rare (120 degrees F. on your meat thermometer). Remove from grill and transfer to a cutting board; cut on the diagonal into thin strips.
Preheat oven to 350 degrees F. Wrap stacked flour tortillas in aluminum foil and heat in oven 15 minutes or until hot. To microwave, wrap a stack of flour tortillas lightly in paper towels and warm on high for 6 or 7 seconds per tortilla.
While the shirt steak is cooking, grill the green pepper and onion slices 1 to 2 minutes or until soft; remove from grill and place on a serving platter. Place cooked steak strips onto the same platter.
For each fajita, fill a warm flour tortilla with cooked steak strips and desired amounts of green pepper and onion slices. Add tomatoes, cheddar cheese, sour cream, guacamole, and salsa as desired; roll up like a burrito and enjoy.
Makes 4 to 6 servings.
In a large re-sealable plastic bag, combine lime juice, vinegar, soy sauce, molasses, cilantro, garlic, cumin, and pepper; set aside.
Fajitas Recipe - How To Make Fajitas: https://whatscookingamerica.net/history/fajitahistory.htm