Mexican Fajitas

Name: Mexican Fajitas
Cuisine: American, Mexican, Latin American
Ingredients: 500g flank steak (or chicken breasts); 1 red bell pepper, thinly sliced; 1 green bell pepper, thinly sliced; 1 yellow bell pepper, thinly sliced; 1 large onion, thinly sliced; 2 tbsp olive oil; 1 tsp ground cumin; 1 tsp paprika; 1/2 tsp chili powder; 1/2 tsp garlic powder; Juice of 1 lime; Salt and pepper to taste; 8 small flour tortillas; Fresh cilantro, for garnish; Sour cream, salsa, and guacamole (optional, for serving)