Combine the marinade ingredients, add the chicken cubes and set aside. Separately, mix together the sauce ingredients. Remove the stalks from the chillies and shake out the seeds from the centre. If using large red chillies cut them into large chunks, or if using smaller chillies then keep them whole.
Heat the peanut oil in a wok over medium heat and add in the chillies and Sichuan pepper corns, stir-frying for just a few seconds while the peppercorns pop and the chillies crisp in the oil.
Add in the chicken and keep it moving so that it doesn’t colour too much. As soon as the chicken turns opaque on its surface, add the garlic, ginger and spring onions. Stir-fry for 1-2 minutes until the chicken is nearly cooked, then add the sauce and toss for a minute or so until the sauce thickens and becomes glossy. Because this dish uses chicken breast (a rarity for stir-fried dishes) in very small pieces, it is important that the chicken is cooked quickly so that it remains tender. Stir in the roasted peanuts and serve.
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