01 - Place watermelon cubes, cucumber slices, mint leaves, and lime juice in blender.
02 - Blend until completely smooth, approximately 30-45 seconds.
03 - Pour mixture through fine mesh sieve into pitcher to remove pulp for smoother texture.
04 - Add sweetener if using and stir until fully dissolved.
05 - Pour in cold sparkling water, gently stirring to combine without losing carbonation.
06 - Pour over ice in glasses, garnish with additional mint leaves and lime wedge.