At least 3 hours before grilling the meat, trim it to remove all fat and gristle. For skirt steak, use a flat metal pounder to tenderize. {This is needed because of the short marinading time.} Put the meat in a shallow glass dish or plastic bag. Combine the marinade ingredients. Marinate for about 3 hours in refrigerator. About 45 minutes before serving, clean the grill surface and rub it with an oil dampened cloth. Preheat the grill for about 30 minutes. Remove the meat from the marinade. Sprinkle the meat and salt and pepper and place it on the grill. Baste with marinade, grill, then turn, baste again and grill until medium rare, about 5-6 minutes in all, or until desired doneness. Remove, cover with foil and keep warm. Heat 2 TBSP oil in a cast-iron skillet over medium-high heat. Add the onions and cook until browned, but still crisp. Remove and add bell peppers. Saute about 2 minutes and add onions. Remove the skillet from the heat. Preheat the oven to 230ºC . Wrap the tortillas or pita breads in foil and heat until warm, 8-10 minutes. {Or zap 'em in a microwave for 15 to 25 seconds per tortilla, depending on your microwaves strength. Or grill 'em on the coals for a few seconds, or in another cast iron skillet for a few seconds.} Cut the beef across the grain into strips about 1 cm thick. Reserve all the juices. Put the skillet back on high heat long enough to get hot, then add the meat. It will sizzle. Turn immediately, then put the onions and peppers on top. Pour the reserved juices on top to create a sizzle. (For an even more dramatic sizzle, you can drizzle the meat and onions with 2 TBSP oil instead of the reserved juices.) Carry the skillet immediately to the table. Squeeze lime juice on top. To serve, use tortillas to enclose meat strips, peppers, onions, pico de gallo, guacamole, and sour cream.