• Make the marinade. 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.
• Marinate the steak. Combine remaining marinade and steak in a large resealable freezer bag; seal and refrigerate for at least 2 hours, or overnight.
• Prep the grill. Preheat the grill to HIGH heat.
• Grill it. Remove the steak from the marinade and lightly pat it dry with paper towels. Add the steak to the preheated grill and cook for 6-8 minutes per side, or until it reaches the desired doneness. Note that flank steak tastes best when cooked to a rare or medium-rare doneness, as it's a lean cut of steak. Refer to the temperature guide in the notes below to cook your steak to your preferred temperature.
• Finish and serve. Remove the steak from the heat and let it rest for 10 minutes. Then, thinly slice it against the grain, garnish with the reserved cilantro mixture, and serve.

Stovetop Method

• Heat a large skillet (preferably a cast-iron grill pan) over high heat until it is hot. Add the steak to the skillet and cook it for 6 to 7 minutes per side, or until desired level of doneness.