Make a marinade by whisking together your soy sauce, honey, sesame oil, garlic, ginger and chili flakes. Pour the marinade over the salmon and set aside in the fridge for at least 30 minutes.
Heat the air fryer to 350°F/180°C.
Lift the salmon fillets out of the marinade (reserve the marinade in the bowl), place them in the air-fryer basket and cook for 7 to 9 minutes, until cooked and flaky.
Meanwhile, tip the reserved marinade into a small saucepan over a medium heat, add ½ cup of water and reduce until glossy. Taste to check the seasoning – you might need to add a splash of rice wine vinegar and honey to balance the flavours. Blitz until smooth if you like.
Serve the salmon with the sauce drizzled over.