Cook the noodles according to the package instructions. Drain and set aside.
In a large skillet, heat the vegetable oil over medium heat. Add the minced garlic and ginger, and sauté for about 1 minute until fragrant.
Add the ground beef to the skillet. Cook, breaking it apart with a spoon, until it's browned and fully cooked (about 5-7 minutes).
Once the beef is cooked, drain any excess fat.
In a small bowl, mix together soy sauce, oyster sauce, brown sugar, and sesame oil. Pour this mixture over the cooked beef in the skillet.
Stir well, ensuring that the beef is evenly coated with the sauce. If desired, add red pepper flakes for some heat.
Add the cooked noodles to the skillet and gently toss everything together until the noodles are heated through and well combined with the beef mixture.
Serve hot, garnished with chopped green onions.