To make the puris, place the semolina, flour and a pinch of salt in a bowl, then gradually add the soda water, stirring continuously until the mixture comes together to form a stiff dough. Place into a flour-dusted bowl, cover with a damp tea towel and leave to stand for 30 minutes.
Meanwhile, blitz all the pani ingredients, ½ a bunch of coriander, a pinch of salt and pepper and 200ml of water in a liquidiser until smooth. Line a sieve with a double layer of muslin, place over a large bowl, then pour in the tomato mixture and leave to strain – you’ll end up with a beautiful, intense, flavoured water.
Meanwhile, make the green salsa. Roughly chop and add the ginger to a liquidiser with the remaining salsa ingredients. Blitz until smooth, then season to taste and transfer to a small bowl.
For the spiced chickpeas, heat a lug of olive oil in a medium frying pan over a medium heat. Add the cumin, curry leaves and cinnamon, then fry for around 3 minutes, or until nicely toasted. Stir in the chickpeas, then add the tamarind paste or chutney and cook for a further 3 minutes to warm through, shaking the pan occasionally. Transfer to a plate and set aside.
Shape the puri dough on a flour-dusted surface into a long sausage shape, roughly 40cm in length, then take small lumps of dough and roll into rough grape-sized pieces with your hands. Roll the dough out into thin, flat circles, roughly 7cm in diameter.
Place a large, deep pan over a high heat, add the vegetable oil and allow it to get really hot. To test if it’s hot enough, drop a tiny piece of dough into the pan – if it floats to the surface and starts to sizzle, it’s about right. Using a slotted spoon, carefully lower 3 to 4 dough circles into the pan. Fry for 2 to 3 minutes, or until puffed up, using the spoon to push them under the oil, then carefully flip them over and continue cooking for 2 minutes, or until golden and crisp. Transfer to a double layer of kitchen paper to drain, then repeat with the remaining dough.
Meanwhile, finely chop the fennel, radishes, onion and cucumber, then place into separate bowls.
To serve the puris, smash a hole in the top and spoon some chickpeas, green salsa and chopped vegetables inside. Drizzle in a little of the pani, pick over a few of the remaining coriander leaves and tuck in.