In a mixing bowl, combine olive oil, lime juice, garlic powder, cumin, salt, and pepper to create a marinade. Coat the steak and let it marinate for at least 1 hour.

Preheat grill to medium-high heat. Grill the marinated steak for 5-7 minutes per side until medium-rare. Let it rest for 5 minutes before slicing.

In a skillet, heat olive oil over medium heat. Add sliced onions and bell peppers, sautéing for 5-8 minutes until soft and caramelized.

Warm tortillas in a skillet over medium heat for 30 seconds on each side or microwave wrapped in a damp paper towel for 15 seconds.

Assemble burritos with warm tortillas, filling with steak, sautéed veggies, guacamole, and salsa. Roll tightly and tuck in the sides.

Slice burritos in half and serve immediately with extra guacamole or salsa on the side.