Source: Basic fajita recipe is from the Johnson family which owns the Macayo chain.
Marinade
1 tablespoon salt
1/4 tablespoon white pepper
1/4 lime, squeezed
3 cloves fresh garlic, chopped
2 tablespoons vegetable oil
In a large bowl, whisk together all Marinade ingredients. Put meat in marinade and set aside for at least one hour.
Preheat oven to 200 degrees F. Set tortillas in for 1 to 3 minutes, to warm. Remove and put into a covered basket.
1 pound beef skirt (flank steak) or chicken breast,
sliced into 1/4 x 3-inch long strips
1 large whole onion, chopped
1/2 cup olive oil or chili oil
Heat a large skillet and add olive oil. Add marinated meat and onion and saute.