Preheat a grill or grill pan to medium. In a large bowl, combine the pork, balsamic vinegar, grill seasoning, fennel seeds, crushed red pepper and garlic; season with salt and pepper. Divide into 4 equal portions; form each into 3 meatballs. Press 1 grape into each meatball, then pinch the meat to seal. Coat the meatballs with 2 tablespoons EVOO and thread onto skewers. Cover and grill, turning, until firm and cooked through, about 18 minutes.