In a bowl, combine cilantro, olive oil, soy sauce, orange juice, lime juice, garlic, jalapeno, cumin and salt and pepper.
Place the steak on a clean, flat surface. Cover with plastic wrap and using a mallet, pound the steak to help tenderize the meat.
Add flank steak to bowl. Cut the steak in half or fold the meat if it is too big to fit into bowl.
Pour ingrediants from first step into bowl and using your hands cover the meat with the marinade.
Place lid on the bowl or cover with plastic wrap. Put the bowl into the fridge overnight.
Light the mesquite charcoal. When charcoal begins to glow, it's ready for the meat.
Place the steak on the grill and cover the grill to reduce the flames.
After about 5 minutes, remove the lid from the grill and flip the steak.
Remove the steak when cooked to desired temperature. Don't overcook the steak or it will become tough.,
Let the steak rest for a few minutes. Cut the meat (against the grain) into small pieces.