In a mixing bowl, combine orange juice, lime juice, soy sauce, minced garlic, chopped cilantro, cumin, chili powder, salt, and pepper.
Place the flank or skirt steak in a ziplock bag or airtight container and pour the marinade over it.
Seal the bag or container and refrigerate for at least 2 hours, or preferably overnight, to allow the flavors to infuse into the meat.
Preheat your grill to medium-high heat.
Remove the steak from the marinade and discard any excess marinade.
Grill the steak for 4-6 minutes per side, or until it reaches your desired level of doneness.
Once cooked, remove the steak from the grill and let it rest for a few minutes before slicing it thinly against the grain.
Serve the carne asada with warm tortillas, salsa, guacamole, and your favorite toppings.