Drain and cut the preserved lemons in half, removing any seeds. Chop finely and set aside. Finely chop the chillies, and pick and finely chop the coriander.
Heat a saucepan to a medium heat, and add a splash of oil. Add the mustard seeds and when they pop, add the ginger, chilli, curry paste and tomato purée. Stir and fry for a moment before adding the chopped lemon, the zest and juice from the limes and the coriander. Season, cook for a minute, transfer to a bowl and allow to cool before serving with poppadoms and a cold beer.