Bring a large pot of salted water to a boil. Add the spaghetti and cook according to package instructions until al dente, about 9-11 minutes. Reserve 1/4 cup pasta water before draining.

In a large skillet, heat 1-2 tablespoons of neutral oil over medium-high heat. Add ground beef, breaking it into pieces. Cook for about 5-7 minutes until browned. Drain excess fat if needed.

Reduce heat to medium. Stir in minced garlic and grated ginger, cooking for 1 minute until fragrant.

Pour in soy sauce, chili oil, brown sugar, and rice vinegar. Simmer for 2-3 minutes until the sauce thickens slightly.

Add spaghetti to the skillet and toss with the sauce. If too thick, stir in reserved pasta water gradually.

Remove from heat and drizzle with sesame oil. Stir in green onions and optional sesame seeds.

Serve immediately, garnished with chili oil and sesame seeds. Pair with garden salad if desired.