Fuchsia Dunlop's Cold Chicken with a Spicy Sichuanese Sauce (Liang Ban Ji)

INGREDIENTS

• About 3/4 lb (300–350g) cold, cooked chicken, without bones
• 3 spring onions
• 1/4 teaspoons salt
• 1 tablespoon sesame seeds (optional)
•  
• 2 tablespoons light soy sauce
• 1 1/2 teaspoons Chinkiang (brown rice) vinegar
• 1 1/2 teaspoons sugar
• 1 tablespoon chicken stock
• 3–4 tablespoons
• with 1/2 tablespoon of its sediment (or more, if you wish)
• 1/4–1/2 teaspoon ground, roasted Sichuan pepper, to taste
• 1 teaspoon sesame oil