Mix together first nine ingredients. In a large heavy duty, zip top bag, put pieces of skirt steak or chicken breast and pour in marinade. Seal bag, removing as much air as possible. Allow steak to marinate for at least 1 hour in refrigerator.
Just before making fajitas, heat a heavy skillet over med high heat. Add 2 Tablespoons of your favorite oil. Stir-fry sliced onion and bell pepper til crisp tender. Remove from pan.
Add beef or chicken strips and a quarter to half cup of the marinade. simmer until done. Add vegetables, stir.
Heat vegetables through and serve with tortillas, pico de gallo, guacamole, shredded cheese and sour cream as desired.
*If you prefer, you can marinate your chicken or steak whole and grill before slicing and serving. I've done it both ways, sliced, marinated, and cooked in skillet ~and marinated whole and grilled. Excellent both ways!!