Cook the Spaghetti: Bring a large pot of salted water to a rolling boil over high heat. Add the spaghetti and cook according to package instructions until al dente, about 8-10 minutes. Reserve 1/4 cup of pasta water, then drain and set aside.

Brown the Ground Beef: In a large skillet or wok, heat 2 tablespoons of neutral oil over medium-high heat. Add the ground beef, breaking it apart, and cook until browned and fully cooked, about 5-7 minutes. Drain excess fat.

Sauté Garlic and Ginger: Reduce heat to medium, then add minced garlic and grated ginger to the skillet. Sauté for about 1 minute until fragrant.

Mix in the Sauce Ingredients: Pour in soy sauce, chili oil, brown sugar, and rice vinegar. Stir to combine and simmer for 2-3 minutes until thickened slightly.

Combine Spaghetti with the Sauce: Add the drained spaghetti to the skillet and toss with the beef and sauce mixture. Add reserved pasta water as needed for the desired consistency.

Finish with Seasonings: Drizzle toasted sesame oil over the spaghetti and toss. Sprinkle with chopped green onions and sesame seeds before serving.