Peel the cucumber and cut into small cubes (about 5 mm).
Place cucumber cubes in a sieve and sprinkle with a little regular salt.
Let the cucumber drain for 15 minutes, then squeeze out the liquid.
Slice the red onion very thinly.
Rinse and finely chop the fresh herbs.
Place yogurt in a bowl and stir until smooth.
Add the drained cucumber and red onion.
Stir in the chopped mint and coriander.
Season with roasted cumin, black salt, and chaat masala.
Let the raita chill in the fridge for at least 30 minutes before serving.