In a food processor, blend the Szechuan pepper, garlic, ginger, orange zest, spring onions and chilli to a rough paste.
Add the honey, soy and oils and whizz to a fairly smooth consistency. Season generously with salt and freshly ground black pepper and transfer to a large bowl.
Add the chicken pieces and mix well until evenly coated. Cover and leave to marinate in the fridge for at least 4 hours, preferably up to 24 hours, turning occasionally.
Remove from the fridge at least 30 minutes before cooking to bring the chicken to room temperature.