Combine all the ingredients for the salmon, apart from the fish, in a bowl. Add the salmon and turn to coat.
Heat a frying pan and, once hot, add the marinated fish skin-side down. Cook for three minutes, or until the skin turns crispy, before turning to cook on the other side for another three minutes.
While the fish is frying, heat the oil for the sauce in another pan. Once hot, add the cumin, fennel and nigella seeds. Once they start to sizzle, add grated ginger, garlic and chilli powder or fresh chillies, and cook for a minute.
Add the puréed tomatoes, stir and cook for three to four minutes. Then add tamarind chutney or pomegranate molasses, sugar, salt, coriander and hot water. Mix all together, cover the pan and cook on a low heat for about five minutes.
Place the glazed cooked fish into the sauce carefully, skin side up, and cook for two to three minutes before serving.