01 - Combine sliced flank steak with 1 tbsp soy sauce, Shaoxing wine, and cornstarch in a small bowl. Mix thoroughly until well coated and set aside to marinate for 10 minutes.
02 - Blanch green beans in boiling water for 2 minutes until bright green and just tender. Drain immediately and rinse under cold water to stop cooking. Set aside.
03 - Heat 1 tbsp vegetable oil in a large wok or skillet over high heat. Add marinated beef in a single layer and stir-fry for 2–3 minutes until browned but still tender. Remove beef from wok and set aside.
04 - Add remaining 1 tbsp oil to the wok. Add Szechuan peppercorns and dried red chilies; stir-fry for 30 seconds until fragrant and aromatic, being careful not to burn them.
05 - Add minced garlic, ginger, and half the sliced scallions to the wok. Stir-fry for 30 seconds until fragrant, releasing their aromatic oils.
06 - Add blanched green beans to the wok; stir-fry for 2–3 minutes until they begin to blister and develop slight char marks.
07 - Return beef to the wok. Add chili bean paste, light and dark soy sauces, black vinegar, sugar, and sesame oil. Toss everything together vigorously for 1–2 minutes until all components are well coated and heated through.
08 - Transfer to a serving platter, garnish with remaining scallions, and serve immediately while hot with steamed jasmine rice.