In a large mixing bowl, combine ground beef, breadcrumbs, egg, minced garlic, grated ginger, and soy sauce. Mix until just combined, then roll into 1-inch meatballs.

Heat oil in a skillet over medium heat. Add meatballs in a single layer and cook for about 8-10 minutes, turning halfway until golden brown.

In the same skillet, whisk together soy sauce, brown sugar, gochujang, rice vinegar, minced garlic, grated ginger, and sesame oil. Simmer for 3-4 minutes until thickened.

Return meatballs to the skillet, tossing gently in the sauce and cooking for an additional 2 minutes.

Scoop rice into bowls, top with glazed meatballs, and add sliced cucumber, julienned carrots, and chopped green onions.

Garnish with sesame seeds and additional gochujang if desired. Serve warm.