In a bowl, combine beef strips with soy sauce, Shaoxing wine, and cornstarch. Let marinate for 10-15 minutes at room temperature.
In a small bowl, whisk together all sauce ingredients until cornstarch dissolves. Set aside.
Heat a large wok or skillet over medium-high heat. Add 1 tablespoon oil, then the Szechuan peppercorns and dried chilies. Stir-fry for 30-45 seconds until fragrant but not burnt, then remove and set aside.
Increase heat to high. Add remaining 1 tablespoon oil to the same wok. Once shimmering, add marinated beef in a single layer. Sear for 1 minute without moving, then stir-fry for another minute until just browned. Remove beef and set aside.
Reduce heat to medium. In the same wok, add garlic, ginger, and white scallion parts. Stir-fry for 20 seconds until aromatic.
Return cooked beef, chilies, and peppercorns to the wok. Pour in the sauce mixture and green scallion parts. Toss everything vigorously for 1-2 minutes until the sauce thickens and coats the beef evenly and beef reaches an internal temperature of 145°F (63°C).
Transfer to a serving plate over steamed rice. Garnish with sesame seeds and fresh cilantro. The dish should sizzle from the residual heat.