Heat a skillet over medium heat and cook the ground beef, breaking it apart, until browned. Drain extra grease if needed.
Stir in garlic and ginger and cook for 30 seconds to 1 minute until fragrant.
In a small bowl, mix soy sauce, brown sugar, sesame oil, rice vinegar (if using), and red pepper flakes (if using).
Pour the sauce into the skillet and stir to coat the beef. Simmer for 2–3 minutes until slightly thickened and glossy.
Serve the beef over warm rice and top with green onions, sesame seeds, and optional veggies.