- Stir together ponzu sauce and rice vinegar in a medium bowl. Add carrot and ginger and toss well to coat. Cover and refrigerate for 15 minutes, or up to 3 hours.
- Cook meatballs in a medium skillet over medium heat for 5 minutes, or until heated through and browned, turning occasionally. Reduce heat to low and add teriyaki sauce; cook for 2 minutes more or until meatballs are nicely glazed.
- Open rolls by cutting in half horizontally without cutting all the way through. Spread with equal amounts of mayonnaise, and then fill with meatballs and vegetables. Drizzle with any remaining sauce left in pan and sprinkle with cilantro leaves, if desired.
*Frozen meatballs vary in size. If large, serve 4 meatballs in each roll. If small, serve 5 meatballs in each roll.