For marinade: Combine garlic, salt, cumin, chili powder, crushed red pepper, oil, and lemon juice in a medium-size bowl.
- 1 clove Garlic
- 1 teaspoon Chili Powder
- 1 1/2 teaspoons 1½ Ground Cumin
- 1 1/2 teaspoons Salt
- 1/2 teaspoon Crushed Red Pepper
- Lemon Juice
- 3 tablespoons Olive Oil
Score skin of beef or chicken with cross-hatched, diamond-shaped marks and rub meat with marinade. Refrigerate for at least 2 hours.
Preheat grill to 350°F (medium heat).
Place onion, green onion, and green and red peppers in aluminum foil and add olive oil.
Seal foil and place on grill for 7 minutes, then remove and set aside.
Grill beef or chicken for 5 to 8 minutes, or until internal temperature of chicken reaches 165°F, or beef temperature reaches 160°F.
Remove from heat, wrap in foil, and let rest for 5 minutes.
When ready to serve, slice beef or chicken into strips and transfer to bowl with the juices.
Serve with warm corn tortillas, grilled onion mixture, avocado, hot sauce, salsa, sour cream and/or freshly chopped tomatoes.