In a large bowl or zip-top bag, combine olive oil, orange juice, lime juice, garlic, cumin, chili powder, smoked paprika, oregano, salt, and pepper. Mix well, then add the flank steak, ensuring it’s fully coated. Seal and marinate in the refrigerator for at least 2 hours, or overnight for best flavor.

Remove the marinated steak from the refrigerator and let it come to room temperature for about 20 minutes. Preheat your grill to medium-high heat. Grill the steak for 4-5 minutes on each side until it develops a beautiful sear and reaches medium-rare doneness, at 135°F internal temperature.

Once grilled, transfer the steak to a cutting board and let it rest for 5-8 minutes. Slice against the grain into bite-sized pieces.

While the steak rests, warm your tortillas in a skillet or on the grill for about 30 seconds per side. Keep them wrapped in a clean kitchen towel until ready to serve.

To assemble, spread mashed avocado on each warmed tortilla, topping with slices of the grilled steak. Sprinkle with cotija cheese, diced onions, and fresh cilantro. Serve with lime wedges on the side.