Mix together the buttermilk and salt, then add the chicken wings. Make sure the meat is fully coated, then cover and leave to brine in the fridge overnight.
Heat a deep-fat fryer to 180C. CAUTION: hot oil can be dangerous. Do not leave unattended.
Mix the three flours together in a bowl.
Remove the wings from the buttermilk and coat in the flour mix.
Carefully lower the wings into the hot oil and fry for 6–8 minutes until cooked through and golden. You may have to do this in batches.
Meanwhile, tip all the sauce ingredients into a pan with a pinch of salt and bring to the boil. Simmer for 5–10 minutes, or until thick and sticky.
Garnish the wings with the lime zest and juice, coriander and spring onions and serve with the sauce alongside for dipping.