Combine lime juice, 1 tablespoon olive oil, cumin, salt, garlic, red pepper and black pepper in a glass bowl. Add beef and allow to stand, at room temperature, 30 minutes. Set skillet temperature to 350° F. Add remaining 1 tablespoon olive oil, onion and green/red bell pepper and stir gently. Cover and cook 1 to 2 minutes or until vegetables are tender. Remove vegetables and keep warm. Drain meat, discard marinade and place meat in skillet. Saute meat 7 to 9 minutes or until done. Meanwhile, wrap tortillas in aluminum foil and heat in 350° oven for 5 minutes. To assemble, spoon about 1/4 of meat and vegetables into center of each warmed tortilla. Sprinkle with 2 tablespoons cheese. Roll tortilla and place on serving plate. Garnish, as desired, with guacamole, salsa, sour cream and/or chopped tomatoes.