In a bowl, combine olive oil, lime juice, garlic, cumin, chili powder, black pepper, and salt.
Place the flank steak in a large resealable bag.
Pour the marinade over the steak, ensuring it is well coated.
Seal the bag and refrigerate for at least 2 hours, or overnight for best flavor.
Preheat your grill to medium-high heat.
Remove the steak from the marinade and discard the marinade.
Grill the steak for about 5-7 minutes on each side for medium-rare.
Use a meat thermometer to check for an internal temperature of 135°F.
Remove the steak from the grill and let it rest for 10 minutes.
Slice the steak against the grain and serve.