Marinade is the key here. Mine is an a 50/50 mix of soy sauce and crushed pineapple (pineapple juice will also work). Marinade 4-6 hours or overnight is fine.
- grill skirt steak on each side on hot grill (300 degrees at least) for 3 minutes per side OR until it reaches medium rare
- slice against the grain into fajita size slices
- heat flour tortillas in skillet until warm (skillet crisps them rather than using a microwave)
- serve with cilantro, cojita cheese and your favorite salsa
- squeeze fresh lime on top of each taco