Chickpea and tuna ‘chaat’: Rosheen Kaul recipe

400g can chickpeas, drained
½ red onion, diced
1 small tomato, diced
1 tbsp lime juice
2 tsp chaat masala (see notes)
salt to taste
2 x 180g cans high-quality tuna in oil, drained
olive oil
½ bunch mint (about 25g), leaves picked
½ bunch coriander (about 25g), leaves picked
1 green chilli, thinly sliced
1 tbsp date and tamarind chutney (see notes)
1 tbsp Greek yoghurt thinned with 1 tsp water
2 tsp sev (see notes)