Heat a large skillet over medium-high heat. Add beef and cook, stirring and crumbling into small pieces until browned, 5 to 7 minutes. Drain excess grease.
Stir in garlic, ginger, and sesame oil and cook until fragrant, about 2 minutes. Stir in soy sauce, brown sugar, and red pepper. Cook until beef absorbs some sauce, about 7 minutes. Add 1/2 of chopped green onions.
Serve over hot cooked rice; garnish with sesame seeds and remaining green onions.