How to Make It
Place chopped cucumbers in a ziplock plastic freezer bag. Seal and freeze at least 4 hours or up to overnight.
Stir together salt, chili powder, and sumac in a small bowl. Spread mixture evenly over a small plate. Add lime juice to blender. Working with 1 glass at a time, rub the rims of 8 rocks glasses with reserved squeezed limes; roll rims in salt mixture until completely coated.
Transfer frozen cucumbers to blender with lime juice; add ice cubes, coconut water, tequila, simple syrup, and chopped cilantro. Process until smooth, about 2 minutes.
Divide cucumber mixture evenly among prepared glasses; garnish glasses with cucumber slices and cilantro leaves. Serve immediately.
Sprinkle any remaining chili-sumac salt over raw fruits and veggies (such as cucumbers, radishes, jicama, or mango). Add a squeeze of lime and some chopped cilantro for a crunchy, refreshing snack.