In a mixing bowl, combine olive oil, fresh orange juice, lime juice, minced garlic, ground cumin, chili powder, smoked paprika, dried oregano, salt, and black pepper. Whisk until well blended. Place the flank or skirt steak into a resealable plastic bag or bowl, pour the marinade over, and ensure it's coated evenly. Seal and refrigerate for at least 2 hours, or overnight for the best flavor infusion.

Remove the marinated steak from the refrigerator and allow it to come to room temperature for about 15 minutes. Preheat your grill or skillet to medium-high heat (around 400°F). Once hot, place the steak on the grill and cook for 4-5 minutes per side for a medium-rare finish. Look for a nice caramelization and grill marks forming, ensuring the steak is cooked to your desired doneness.

Once grilled to perfection, remove the steak from the heat and let it rest on a cutting board for 5-8 minutes. This step is crucial for keeping the juices sealed inside the meat. After resting, slice the steak against the grain into thin strips, then chop these pieces into bite-sized morsels, ready to fill your carne asada tacos.

As you prepare the meat, warm the corn or flour tortillas. You can do this by briefly heating them over a gas flame or in a dry skillet over medium heat, just until soft and lightly charred—about 30 seconds per side. Once warmed, stack the tortillas and wrap them in a clean towel to keep them warm and pliable for assembly.

To assemble your easy & authentic carne asada tacos, begin by mashing ripe avocado onto each warm tortilla. Add a generous portion of the sliced carne asada on top. Sprinkle with cotija cheese and diced onion, then top with freshly chopped cilantro. A squeeze of fresh lime juice over the fillings enhances the freshness beautifully.

Arrange the assembled tacos on a serving platter. If desired, include optional toppings like pico de gallo, sliced radishes, lime crema, or chipotle sauce for added flavor and texture. These carne asada tacos are now ready to be served, offering a delightful experience of vibrant flavors and deliciousness, perfect for any gathering.