Place the steak, lime juice, garlic powder, salt and pepper into a large resealable bag, distribute the marinade evenly, and refrigerate for 3-12 hours. Start your Grill on 'smoke' with the lid open until a fire is established in the burn pot (3-7 minutes). Preheat to 400F. Place the steaks on the grill, and grill them for 4-8 minutes, then flip the steaks and grill for an additional 4-8 minutes. Remove steaks from the grill, loosely cover them with foil, and let them sit for 5-10 minutes. Next chop the steaks into pieces, and serve with tortillas and any desired toppings.