In a large mixing bowl, combine orange juice, olive oil, cilantro, lime juice, lemon juice, white wine vinegar, cumin, salt, and pepper, jalapeno, and garlic; whisk until well combined. Reserve ⅓ cup of the marinade; cover the rest and refrigerate.
Combine remaining marinade and steak in a large resealable freezer bag; seal and refrigerate for at least 2 hours, or overnight.
Preheat the grill to HIGH heat.
Remove steak from marinade and lightly pat dry with paper towels.
Add the steak to the preheated grill and cook for another 6 to 8 minutes per side or until desired doneness. Note that flank steak tastes best when cooked to rare or medium rare because it's a lean cut of steak.
Remove from heat and let the steak rest for 10 minutes. Then, thinly slice it against the grain, garnish with reserved cilantro mixture, and serve.