Cook the Noodles: Bring a pot of water to a boil and cook the noodles according to package instructions until al dente. Drain and rinse under cold water to stop the cooking process. Set aside.

Prepare the Sauce: In a small bowl, combine soy sauce, black vinegar, crushed red chili flakes, and sesame seeds. Mix well and set aside.

Infuse the Oil: Heat 4 tablespoons of oil in a small pan over medium heat. Add Sichuan peppercorns (if using) and toast them until fragrant. Remove the peppercorns and discard, keeping the infused oil in the pan.

Garlic and Chili Oil: Add the minced garlic to the infused oil and cook until fragrant but not burnt, about 1-2 minutes. Add homemade chili oil and stir for another 30 seconds. Remove from heat.

Mix the Noodles: In a large mixing bowl, combine the cooked noodles and the prepared sauce. Pour the garlic-chili oil mixture over the noodles and toss everything together until the noodles are well coated.

Serve: Divide the noodles into serving bowls. Top each serving with sliced cucumber, chopped cilantro, and green onions. Add a soft-boiled or fried egg on top if desired.

Garnish and Enjoy: Sprinkle some extra sesame seeds over the noodles for added texture and flavor. Serve immediately and enjoy the fiery, garlicky goodness!