Place the seeded and cubed watermelon along with the water into a blender. Blend until smooth, then add granulated sugar, starting with the amount listed and adjusting to taste. Blend again to mix thoroughly until the sugar is dissolved and the mixture is smooth. I like to taste the puree here and add a little more sugar if the watermelon isn't very sweet.

Cut each lime wheel in half. Place half a lime wheel and 3 fresh mint leaves into each of 8 serving glasses. Use a cocktail muddler to gently crush the mint and lime together, releasing the mint oils and lime juice to flavor the drink's base.

Fill each glass with about 1 cup of ice cubes, or as much as needed to nearly fill the glass. This keeps the drink cold and refreshingly crisp.

Pour the blended watermelon mixture from Step 1 over the ice, mint, and lime in each glass. Stir gently to combine. Serve immediately, garnished with additional mint leaves or lime wheels if desired. For an extra burst of flavor, I sometimes add a splash of sparkling water to the top before serving.