Wash, then part-peel the cucumber, leaving some stripes of the peel along its length. Halve the cucumber lengthwise, and using a teaspoon, scrape out the seeds and pulp. Set pulp aside. Now cut the cucumber halves lengthwise into thin batons, then cross chop these into small cubes. Place into a bowl.
Add salt, jaggery, mint and coriander leaves and cumin seeds to cucumber and toss well.
Using a sieve and a spoon, extract the juice from the cucumber pulp and pour over the cucumber.
Add yoghurt to cucumber and stir well. Cover, and refrigerate for one hour or until ready to serve.
to serve
When ready to serve, sprinkle with garam masala and garnish with coriander and mint leaves.