In a mixing bowl, combine fresh lamb leg pieces with soy sauce, Shaoxing wine, and a pinch of salt. Mix thoroughly and marinate for at least 20 minutes.

In a small bowl, mix together cumin powder, Sichuan chili flakes, sugar, and Sichuan peppercorns. Stir until well combined.

Drain the lamb pieces and sprinkle cornstarch evenly over them. Toss to ensure each piece is coated.

Heat a large skillet over medium-high heat and add peanut oil. Sear the lamb in a single layer for 1-1.5 minutes on each side until golden brown. Set aside.

In the same skillet, add dried chili peppers, minced ginger, sliced garlic, and onion. Stir-fry for about 1 minute until onions soften.

Return the cooked lamb to the skillet and sprinkle the spice mix. Toss until evenly coated and adjust salt if necessary. Cook for 1 minute.

Remove from heat and stir in chopped cilantro. Serve immediately.