Dry fry mustard, cumin, and coriander seeds in a hot pan until seeds pop.
Grind the toasted spices into a fine powder using a pestle and mortar.
Whisk the spice powder with remaining paste ingredients in a bowl.
Preheat the grill to its highest setting.
Smear half the paste onto pollack fillets and grill for 3-4 minutes until cooked.
Heat a frying pan and sauté shallots in oil for 2 minutes.
Add remaining spice paste to the pan and cook for 1 minute.
Stir in the chickpeas and cook until heated through.
Add tomatoes and coriander then season with salt and pepper.
Serve the pollack atop the chickpeas with a lime wedge.