In a zip top/resealable bag combine the beer, orange juice, olive oil, lime juice, cilantro, garlic, and salt.
Remove ¼ cup of the marinade and reserve it for later; keep covered and refrigerated until ready to use.
Add the flank steak to the marinade in the bag and coat it all around. Seal and marinate for 1 hour on the counter, or for 2 hours in the fridge.
Preheat an outdoor grill to HIGH, about 550˚F.
Brush the grill grates with vegetable oil.
Remove the steak from the marinade; discard marinade.
Place steak on the grill and cook for 6 to 7 minutes per side, or until internal temperature registers at 130˚F to 135˚F.
Remove from grill and let rest 8 to 10 minutes.
Thinly slice the steak against the grain.
Serve with tortillas, pico de gallo, guacamole, and lime wedges.