Combine diced chicken with 1 tablespoon soy sauce, 1 tablespoon cornstarch, and 1 teaspoon Shaoxing wine in a bowl. Mix with your hands until each piece is coated and there's no visible cornstarch left. Rest 15 minutes at room temperature while you prep everything else. The cornstarch hydrates and forms a protein-bound layer during this time.

In a small bowl, whisk together remaining 1 tablespoon soy sauce, 2 tablespoons black vinegar, 1 tablespoon sugar, 2 teaspoons Shaoxing wine, 1 tablespoon cornstarch, and 2 tablespoons water. Set next to the stove. This is the only sauce action that happens during cooking — measure now, not later.

Have everything else within arm's reach of the stove: dried chilis, crushed peppercorns, sliced garlic, julienned ginger, scallion whites, and peanuts. From the moment the oil hits the pan, you have 6 minutes of constant motion. Anything not prepped now will get burned.

Heat 2 tablespoons oil in a wok or large skillet over high heat until shimmering. Spread the marinated chicken in a single layer and let it sit untouched for 1 minute to develop a sear. Stir-fry another 2 minutes until pieces are no longer pink. Transfer to a clean plate — it'll finish cooking later. Don't crowd the pan; if your skillet is smaller than 12 inches, sear in two batches.

Add the remaining 1 tablespoon oil to the empty pan, still over high heat. Add dried chilis and crushed Sichuan peppercorns. Stir 15 seconds — they'll darken and release a sharp peppery aroma. Add garlic, ginger, and scallion whites. Stir another 20 seconds until fragrant. Don't let the chilis burn black; pull the pan off heat briefly if needed.

Return chicken to the pan. Stir the sauce one more time (cornstarch settles fast) and pour it in. Toss constantly for 30–45 seconds — the sauce will thicken and turn glossy, coating every piece. Add roasted peanuts and toasted sesame oil. One final toss to distribute. Off the heat.