In a bowl, mix the sliced beef with soy sauce, Shaoxing wine, cornstarch, and sesame oil. Let marinate for at least 15 minutes.
Toast the Sichuan peppercorns in a dry pan for 1-2 minutes until fragrant. Grind them into a coarse powder.
Heat vegetable oil in a wok over high heat. Stir-fry the marinated beef in batches until browned. Remove and set aside.
Add dried chilies, garlic, and ginger to the wok. Stir-fry for 30 seconds until fragrant.
Return the beef to the wok. Add soy sauce, dark soy sauce, sugar, and ground Sichuan peppercorns. Toss well to coat.
Garnish with scallions and serve hot with steamed rice or noodles.