Add yoghurt to a medium bowl. Add chopped onion, cucumber, tomato, coriander and cucumber seed to the yoghurt. Mix well.
Add salt, pepper and sugar. Mix well.
Toast cumin seeds in a hot, dry pan on medium heat for a few seconds until they start to turn a shade darker and crackle. Remove from heat. Add to the raita.
Add chilled water, a little at a time while mixing gently until you get the consistency you desire. Your raita should be thick and creamy.
Chill the raita in the fridge for at least 1-2 hours before serving. It will stay fresh in the fridge for up to 3 days.
