Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a large bowl, combine the ground chicken, breadcrumbs, chopped green onions, minced garlic, grated ginger, black pepper, and chili flakes (if using). Mix until well combined.
Form the mixture into small meatballs, about 1 inch in diameter, and place them on the prepared baking sheet.
In a separate bowl, whisk together the soy sauce, honey, sesame oil, and rice vinegar until smooth.
Brush half of the honey soy glaze over the meatballs, ensuring they are evenly coated.
Bake the meatballs in the preheated oven for 15-20 minutes, or until they are cooked through and golden brown.
During the last 5 minutes of baking, brush the remaining glaze over the meatballs for an extra sticky finish.
Once done, remove them from the oven and let them cool for a few minutes.
Garnish with sesame seeds and fresh cilantro before serving.