Preheat your oven to 400°F.
In a large mixing bowl, combine the ground beef, breadcrumbs, green onions, soy sauce, sesame oil, garlic, ginger, brown sugar, egg, black pepper, and red pepper flakes. Mix until well combined.
Shape the mixture into meatballs, about 1 inch in diameter, and place them on a baking sheet lined with parchment paper.
Bake in the preheated oven for 20-25 minutes, or until cooked through and browned.
While the meatballs are baking, prepare the spicy mayo dip by whisking together the mayonnaise, sriracha, lime juice, and garlic powder in a small bowl until smooth.
Once the meatballs are done, remove them from the oven and let them cool for a few minutes before serving with the spicy mayo dip.