Prepare Steak - Combine all the marinade ingredients in a gallon size seal top plastic bag. Place steak in bag and seal. Let steak marinade in the refrigerator for a few hours and ideally overnight. Remove from refrigerator and heat a cast iron skillet over high heat for a few minutes to get hot. Drain marinade from steak and pat it dry. Cook steak in hot skillet for 3 minutes per side for medium rare. Remove and let sit a few minutes under a tin foil tent and then slice into thin ¼-inch slices at an angle.
3 large Boneless, skinless chicken breasts (for chicken fajitas), 2 lbs Skirt steak or flank steak (for steak fajitas), 2 tbsp Cooking oil, ⅓ cup Lime juice, 2 tbsp Worcestershire sauce, 1 tbsp Soy sauce, 4 cloves Garlic, minced, 3 tbsp Olive oil, 2 tsp Each: ancho chili powder and ground cumin, 1 tsp Each: salt, paprika, and black pepper