Slice the sirloin steaks into thin strips. This makes them perfect for quick cooking and easy eating.
Marinate:
In a bowl, combine 1 1/2 tablespoons olive oil, lime juice, minced garlic, chili powder, cumin, hot pepper flakes, black pepper, and salt.
Add the beef strips to this mixture and stir well to coat them evenly. Set this aside to marinate for a bit to enhance the flavor.
Warm Tortillas:
Preheat your oven to 350°F (175°C). Wrap the tortillas in foil and heat them in the oven for about 6-9 minutes. This makes them soft and pliable, perfect for wrapping.
Cook Veggies:
While the tortillas are warming, slice onions and sweet peppers into strips. Heat some olive oil in a large skillet over medium-high heat.
Add the onions and peppers, cooking for about 4-5 minutes until they're softened but still a bit crunchy. Remove from the skillet and set aside.
Cook Beef:
In the same skillet, add the marinated beef strips. Cook for about 4-5 minutes, stirring occasionally, until they're nicely browned but still juicy.
Return the onions and peppers to the skillet with the beef. Stir everything together for another minute to mix the flavors.
Assemble and Serve:
Lay out a warm tortilla. Spoon a portion of the beef, onion, and pepper mixture down the center.
Add your favorite toppings like salsa, sour cream, cheese, and tomatoes. Fold the bottom of the tortilla up over the filling, and fold the sides in, overlapping at the center.