O.K., folks! There is NO such thing as a CHICKEN, SHRIMP. SQUID or other type fajita EXCEPT BEEF! The term fajita is the American counterpart of the Mexican term arracheras, which is the tough and membranous cut from the underbelly of BEEF cattle. The chicken, etc. is simply a piece of chicken wrapped in a tortilla and seasoned with appropriate spices.
Fajitas start with the marinade. These marinades for beef fajitas rely on the acid ingredients like lime juice not just for flavor, but to tenderize the meat. Some marinades use papaya juice to tenderize and flavor the meat. Beef fajitas should be marinaded for several hours or up to 24 hours. I include only one marinade for beef and (God forgive me!) one for chicken. Some marinades contain fresh or dried chilis as a heat source. There is nothing written in stone when it comes to the ingredients for the marinades. Some have bottled salad dressing, tequila or coca-cola.
There are three choices in cooking fajitas: Grilling, Oven Broiling or Pan-Frying.
Grilling is the traditional method of preparing fajitas. When the coals are ready (NOTICE I said Coals - NOT gas!), drain the marinade from the meat and allow the meat to come to room temperature. Cook about 3 inches above the coals for approximately 6 minutes on each side for skirt steaks between 1 and 1 1/2 pounds. When the meat is cooked to your liking, remove from the grill and let rest for 5 to 10 minutes. Cut across the grain and diagonally into finger-lehgth strips.
Oven broiling (ONLY when the weather is bad and you can't light the grill!) Broil the meat about 4 inches below the broiler for 5 to 6 minutes per side, then let meat rest and slice as above for grilling.
Pan-Frying (ONLY if you have a large cast iron skillet) Drain the meat then cut across the grain, diagonally as above. Fry the strips over high heat, working in batches, if necessary, turning frequently. They should take between 1 1/2 to 2 minutes to cook.
To eat fajitas, you roll them in a flour tortilla (Real Mexicans use CORN tortillas), but NOT by themselves. The proper fajita feast will include a stack of warm tortillas, grilled or fried onions and bell peppers, pico de gallo, guacamole and if you are a YANKEE, a little sour cream!