Wash and trim the cucumbers. If using Persian cucumbers, peeling is optional, their skin is thin and mild.
Roughly chop into 1-inch pieces for easier blending.
Add cucumbers and filtered water to a high-speed blender. (<< Get 15% off if you follow that link!) Blend on high for 30–60 seconds until completely smooth and liquefied.
Place a fine mesh strainer over a bowl or measuring cup and pour the mixture through.
Use the back of a spoon to gently press and extract as much liquid as possible.
Discard the pulp. You should have a vibrant, pale green cucumber juice. Refrigerate until ready to use (best used within 24 hours for optimal freshness.)