In a large skillet, heat the vegetable oil over medium heat. Add the ground beef and cook until browned, breaking it apart with a spatula, about 5-7 minutes.
Add the minced garlic and ginger to the skillet and cook for an additional 1-2 minutes until fragrant.
Stir in the soy sauce, brown sugar, sesame oil, red pepper flakes, and black pepper. Cook for another 2-3 minutes until the sauce thickens slightly.
In a separate large pan, add the chopped napa cabbage and julienned carrot. Cook over medium heat for about 3-4 minutes, stirring occasionally, until the cabbage is wilted.
Combine the wilted slaw with the ground beef mixture and toss to combine. Cook for an additional 1-2 minutes to heat through.
Serve hot, garnished with sliced green onions and sesame seeds.