Cut chicken into ¾–1 inch cubes.
Marinate chicken with salt, Shaoxing wine, and egg white for 15 minutes.
Toss chicken in cornstarch until lightly coated and shake off excess.
Heat oil to 350–360°F and fry chicken in batches for 3–4 minutes until pale golden and cooked through.
Drain well and cool completely in a single layer without stacking.
Freeze chicken pieces on a tray until solid, then bag airtight and label.
For optional chili kit, freeze dried red chilies, whole Sichuan peppercorns, ginger slices, and garlic cloves together.
For second fry, heat oil to 375°F and fry frozen chicken for 2–3 minutes until deeply golden and crisp.
In a wok, leave 2 tbsp oil and heat until lightly smoking.
Add Sichuan peppercorns and dried chilies, then garlic and ginger, tossing quickly.
Add chicken and toss hard, then season with sugar and MSG.
Add scallions and toss for 10–15 seconds before killing the heat.