Wash the bean sprouts thoroughly under cold running, clean water. Trim any long roots or damaged ends. Drain and place them in a large bowl.

Heat the cooking oil in a wok over medium-high heat. Add in the Sichuan peppercorns until they turn to a darker color. Remove them with a spotted sponge.

Add the minced garlic to the hot oil. Stir-fry for about 30 seconds until they become fragrant. Add the washed bean sprouts to the wok. Stir-fry for 2-3 minutes until they begin to wilt slightly but maintain a little crunch.

Fold in the green onion pieces(about 2 inches) and continually stir fry for 30 seconds.

Drizzle the light soy sauce and black vinegar over the sprouts. Stir-fry for an additional minute to evenly coat the sprouts.

Sprinkle with salt, black pepper, and a pinch of sugar (optional) to taste.

Transfer the stir-fried mung bean sprouts to a serving dish. Garnish with chopped red chilis and a sprinkle of roasted sesame seeds. Enjoy your perfect side dish!