Mix the diced chicken with the wine, soy sauce, cornflour mixture and salt in a bowl, cover and leave to marinate in the refrigerator for 1 hour.
For the gong bao stock:
Heat a drizzle of oil in a saucepan and toast the Sichuan peppercorns, then add the remaining stock ingredients. Simmer for 20 minutes and then set aside. Heat the 2 tablespoons of oil in a wok, add the marinated chicken and stir-fry until just cooked through. Stir in the spring onion and celery. Deglaze the pan with a little Shaoxing rice wine, then add enough of the stock so that the chicken is covered in the pan. Boil mixture until the sauce is thick and has reduced enough to coat the chicken.
For the peanut foam:
Mix all ingredients together in a small saucepan and heat gently. Do not bring the mixture to the boil as this will prohibit the foaming. When the peanut mixture is warm blend the surface of the mixture using a stick blender for about 20 seconds to produce a mass of cappuccino-style foam. Just before serving the chicken, throw in the peanuts, decorate the dish with the peanut foam and garnish with air-dried chicken skin, if you like.
Chef's tip:
The quantity of dried chillies specified in based on the Chinese variety, which are quite large and relatively mild. If you are using small dried chillies, halve this quantity; as a general rule, the smaller the chilli, the more lethal it will be.