Prepare the Noodles: If using dried noodles, cook them according to the package instructions until al dente. For fresh noodles, blanch them in boiling water for about 1 minute. Drain and rinse under cold water to stop the cooking process.

Mix the Sauce: In a bowl, combine the sesame paste, light soy sauce, dark soy sauce, Chinese black vinegar, sesame oil, chili oil, sugar, minced garlic, and a pinch of salt. Stir until well blended.

Assemble the Dish: Place the cooked noodles in a serving bowl. Reheat the noodles with hot boiling water, drain quickly, and then add the mixed sauce.

Assemble the Dish: Place the cooked noodles in a serving bowl. Reheat the noodles with hot boiling water, drain quickly, and then add the mixed sauce.

Add Toppings: Top the sauced noodles with green onions, pickled mustard greens, bean sprouts, cilantro, toasted sesame seeds, and crushed peanuts, if using.

Serve: Serve the noodles hot, allowing each person to mix the toppings and sauce into the noodles just before eating.