In a bowl, mix the lime juice, orange juice, minced garlic, chopped cilantro, cumin, chili powder, salt, and pepper. Place the steak in a resealable bag or dish and pour the marinade over it. Seal and refrigerate for at least 1 hour (or up to 4 hours for more flavor).
Grill the Steak:
Preheat a grill or stovetop grill pan over medium-high heat. Remove the steak from the marinade and grill for 4-6 minutes per side, depending on your preferred level of doneness. Let the steak rest for about 5 minutes before slicing.
Slice the Steak:
