Pro tip: Make a double batch of the pickled carrots to toss into green salads or use as a garnish for fish tacos.
Preheat oven to 375°. In small pot, bring rice vinegar, 2 chiles, honey, 1 clove garlic, and 1 tsp. salt to a simmer over medium heat. Remove from heat and add carrots. Chill 30 minutes. Meanwhile, in bowl, mix turkey, ginger, remaining garlic and chiles, 1 tbsp. hoisin, and 1/2 tsp. salt. Shape into 20 two-inch meatballs; transfer to large rimmed baking sheet lined with foil. Bake 15 minutes. Remove from oven; drizzle meatballs with 2 tbsp. hoisin. Broil until browned and bubbly, 3 to 5 minutes. Divide meatballs among buns. Top with remaining 2 tbsp. hoisin, drained carrots, and herbs.