Slice the skirt steaks in half so that each steak is 5-inches long. Pound each steak with a meat mallet until 3-inches wide.
Combine 2 tablespoons balsamic vinegar and 2 tablespoons coconut aminos in a mixing bowl. Add the steaks to the mixture and toss with hands to coat.
Cover and marinate for 30 minutes–2 hours in the refrigerator.
Slice the vegetables into thin strips (about ⅓ cup of each vegetable). Heat a skillet over medium heat with 2 tablespoons olive oil. Add the veggies, 1 tablespoon coconut aminos, 1 tablespoon balsamic vinegar, and garlic. Sauté for 7 minutes, until tender.
Once the steaks have marinated, use tongs to place the veggie mix in the center of each skirt steak. Fold each side toward the center, secure with a toothpick, and season with pepper.
Heat a grill or pan over high heat. Place the skirt steaks on a pan and cook for 3 minutes. Repeat on the other side. Serve hot.