Preheat the oven to 400°F (200°C) or preheat the air fryer.
In a mixing bowl, combine ground chicken, breadcrumbs, green onions, cilantro, egg, garlic, ginger, soy sauce, salt, pepper, and red pepper flakes. Mix well until all ingredients are evenly incorporated.
Form the mixture into meatballs, about 1 to 1.5 inches in diameter, placing them on a lined baking sheet or directly into the air fryer basket.
Bake in the preheated oven for 15-20 minutes or air fry for 12-15 minutes, until the meatballs are cooked through and golden brown.
While the meatballs are cooking, prepare the firecracker sauce. In a small saucepan, combine sweet chili sauce, sriracha, soy sauce, rice vinegar, and sesame oil. Whisk together and heat over medium-low until warmed through.
Once the meatballs are done, drizzle them generously with the firecracker sauce, tossing to coat them evenly.
Serve hot, garnished with additional chopped green onions or sesame seeds if desired.