Place watermelon, juice of 1 lime and 1 teaspoon sugar in a blender and blend until smooth. Set aside.

In the bottom of each glass, muddle 2 mint leaves with 1/2 teaspoon sugar.

Add ice to each glass.

Pour watermelon puree over ice filling each glass about half full.
Add in watermelon puree, filling about 1/2 full.

Top with sparkling water and garnish with mint, lime and watermelon if desired