In a large bowl, combine ground beef, breadcrumbs, egg, green onions, garlic, ginger, soy sauce, sesame oil, and gochujang. Mix until just combined.
Shape into 1 to 1.5-inch meatballs.
Heat a skillet with oil and sear meatballs on all sides until browned.
Place meatballs in a baking dish. In a bowl, mix soy sauce, brown sugar, rice vinegar, and a bit more gochujang. Pour over meatballs.
Bake at 375°F (190°C) for 15-20 minutes or until fully cooked and caramelized.
In a separate bowl, mix mayonnaise and sriracha to taste. Add garlic powder or lime juice if desired.
Serve meatballs with spicy mayo dip. Garnish with sesame seeds and green onions.
