Cube watermelon and cucumber.

Combine watermelon and cucumber in a pitcher or jar.

Pour kombucha over watermelon and cucumber.

Cover and refrigerate for at least 1 hour, or overnight.

Strain kombucha through a fine mesh sieve.

Transfer watermelon-cucumber chunks to a food processor or blender.

Puree the watermelon and cucumber.

Strain the watermelon cucumber puree through a fine mesh sieve and add it to the kombucha.

Stir in soda water and tequila (if using).

Divide the kombucha coolers between glasses.

Garnish with cilantro or mint sprigs and a slice of cucumber.

Add ice if desired.