Pour coconut water into a large pitcher. add the cucumber slices, and place in the refrigerator overnight. For a quick version, muddle the cucumber reserving a few slices for garnish and add the coconut water in to flavor and let it sit for 5 minutes.
Pour the gin and sparkling rose into the cucumber water and stir to combine.
Serve up or over ice. Garnish the glass with a cucumber slice and float one in the drink, if desired.