Method
Prepare your pickled red onions an hour or so ahead
1. Slice the onions and place in a clean jar or bowl. Put the water, wine vinegar, fennel and cumin seeds, salt and sugar into a small pan over a medium heat and stir until the sugar and salt are fully dissolved.
2. Pour the hot pickling liquor over the onions and leave to cool slightly. Pop the lid on (or cover the bowl) and place in the fridge to pickle.
3. To prepare the salmon, cut each fillet into 4 equal-sized chunks. Place these in a bowl with the garlic, ginger and lime juice and mix well.
4. In another bowl, mix the yogurt with the spices and some salt and pepper. Add this spiced yogurt to the salmon and mix well again. Leave to marinate in a cool place for at least 20 minutes, or up to an hour.
5. Meanwhile, if using wooden skewers soak eight of them in water to avoid scorching on the barbecue.
6. Once marinated, thread the salmon onto your skewers, putting 4 chunks onto each skewer.
7. Brush the hot barbecue grid lightly with a little oil then lay the skewers on it. Cook for 2–3 minutes on each side until golden brown and lightly charred.
8. Meanwhile, warm the naan or roti on the edge of the barbecue.
9. Once cooked, transfer the skewers to a warm plate.
10. Serve the skewers on the warm naan or roti. Scatter over a little pickled red onion, some coriander and sliced green chilli. Serve with lime halves for squeezing over, and sweet chilli sauce on the side.