Blend the cod in a food processor until finely minced.
Mix the minced cod, chopped salmon, and lime zest in a large bowl.
Stir in the fennel, coriander, chillies, spring onions, spices, oil, pastes, and lime juice.
Mould the fish mixture onto 12 skewers to form kebabs.
Squeeze any excess water from the grated cucumber.
Combine the cucumber and yoghurt with dill, pepper, and garlic.
Fry mustard seeds, cumin, asafoetida, and curry leaves in oil for 3 minutes.
Mix the fried spice mixture into the prepared raita.
Grill or pan-fry the kebabs until golden brown on both sides.
Serve the kebabs immediately with the raita and boiled basmati rice.