Combine cubed chicken with cornstarch, soy sauce, and rice wine in a bowl. Mix until evenly coated and let sit for 10 minutes. This marinade creates a velvety texture that locks in moisture during cooking.

Whisk together soy sauce, dark soy sauce, vinegar, sugar, cornstarch, and chicken broth until smooth. The cornstarch should dissolve completely to prevent lumps. This glossy sauce is what gives Kung Pao Chicken its signature coating.

Heat oil in a wok or large skillet over high heat until shimmering. Add dried chilies and Sichuan peppercorns, stirring for 30 seconds until fragrant but not burned. The oil should sizzle immediately when aromatics hit the pan.

Add marinated chicken to the hot oil, spreading pieces in a single layer. Let sear for 2 minutes without stirring, then toss and cook another 2 minutes until golden and nearly cooked through. The chicken should have crispy edges while staying tender inside.

Push chicken to one side and add minced garlic and ginger to the empty space. Stir-fry for 30 seconds until fragrant, then mix with the chicken. The garlic should be golden but not dark brown.

Add scallions and peanuts, tossing everything together. Pour the prepared sauce over the mixture and stir rapidly for 1-2 minutes until the sauce thickens and coats everything evenly. The sauce should be glossy and cling to each piece.