In a bowl, combine the tikka paste with the vegetable oil, 50 grams of yoghurt and one tablespoon of sugar. Add the sausages and mix well to coat. Cover and pop in the fridge for 30 minutes to marinate.
To make the raita-Combine 250g Greek Yoghurt, the lemon juice, cucumber, cumin, mint leaves and remaining sugar in a bowl and season with some salt and pepper.
To make the salsa-Combine the pineapple, chilli, tomatoes, spring onions, lime juice and olive oil in a bowl and season with a little salt.
Heat a BBQ grill. Remove the sausages from the marinade and thread them onto 3 metal skewers. Put the skewers onto the grill and close the BBQ lid. Grill for 6-8 minutes each side until cooked and slightly charred.
To serve, top the naan with the sausages and scatter over the mint leaves, coriander and some of the salsa and serve immediately with the raita, remaining salsa, and mango chutney on the side.