Add the cucumbers, water, and sugar to a large blender and blend until smooth.
Strain the liquid into a pitcher to remove any seeds and pulp.
Stir in the lime juice, taste, and add more sugar if preferred.
Serve immediately over ice or chill in the refrigerator for up to 3 days. Garnish with fresh cucumber slices and mint sprigs if desired.
Notes
Agua de pepino can be stored in the refrigerator for up to 3 days. If you can’t finish it within that time, freeze the rest in ice cube trays for up to 3 months!