Take mixi zar, blend watermelon, salt, sugar well. Strain it into a bowl.
Add lemon juice, chopped mint leaves and mix well.
Transfer into a shallow container, cover and freeze for 2 hours.
Scrape out using a fork, again put container in freezer for 2 to 3 hours.
Again Scrape out using a fork.
Take serving glass, pour black grape crush, put scrapped watermelon, garnish with mint spring and serve immediately.