Grilled whole mackerel with ginger masala and onion salad

• 4 x 400g whole mackerel, skin slashed on an angle

For the masala

• 2 dried long red chillies, soaked in hot water for 20 minutes

• 10cm piece of ginger, peeled and roughly chopped

• 2 garlic cloves

• 1 tsp black peppercorns, lightly ground

• 6 cloves

• 1½ tbsp white wine vinegar

• 1 tbsp extra-virgin olive oil

• 1 tbsp brown sugar

• 2 tsp salt flakes

For the onion salad

• 1 white onion, finely sliced in rings

• 6 coriander sprigs, leaves and fine stems picked

• 6 flat-leaf parsley sprigs, leaves picked

• 1½ tsp coriander seeds, lightly toasted and ground

• ½ tsp salt flakes

• juice of 1 lime

• 2 pinches of cayenne pepper

• 1 lime, cut into wedges to garnish