In a small bowl, mix together the mayo and ½ tablespoon hot sauce.
In a large bowl, gently mix together the ground turkey, minced garlic, onion, minced cilantro, fish sauce, 1 tablespoon hot sauce, corn starch, 1 teaspoon sea salt and 1 teaspoon ground black pepper. Using moistened hands, roll mixture into 1-inch meatballs. Arrange on plate.
Preheat oven to 300 degrees. Heat sesame oil in a large skillet over medium-high heat. Add half of meatballs. Sauté until brown and cooked through, turning meatballs often and lowering heat if browning too quickly, about 15 minutes. Transfer meatballs to rimmed baking sheet. Place in oven to keep warm. Repeat with remaining meatballs.
Cut the demi baguette horizontally in half.
Spread the spicy mayo on one side. Arrange 3 meatballs on each sandwich and top with drained pickled vegetables and cilantro leaves.