In a mixing bowl, combine orange juice, lime juice, soy sauce, olive oil, garlic, cumin, black pepper, salt, and oregano. Mix well.

Place the flank steak in a large resealable bag and pour the marinade over it. Seal the bag and refrigerate for at least 1 hour, preferably overnight.

Preheat the grill to high heat.

Remove the steak from the marinade and discard the marinade. Grill the steak for about 5 minutes on each side for medium-rare, or until desired doneness.

Let the steak rest for 5 minutes before slicing it against the grain.

Serve the sliced carne asada with warm corn tortillas and toppings such as cilantro, onion, radishes, and lime wedges.