Prep the produce: Wash everything well. Peel the lemon (and ginger, if using).
Core the apple. If your cucumber has thick skin or a waxy coating, peel it.
Chop for blending: Cut cucumber and apple into chunks. Tear mint leaves off the stems.
Roughly chop spinach or kale.
Blend the base: Add cucumber, apple, mint, spinach/kale (if using), coconut water, and 1/2 cup cold water to a blender. Add ginger or celery if you like.
Season and blend: Add a small pinch of sea salt and squeeze in the lemon or lime. Blend on high until very smooth, 30–60 seconds.
Taste and adjust: If it’s too strong, add more water or ice.
For more zing, add extra lemon. For more sweetness, blend in a teaspoon of honey or maple.
Strain (optional but recommended): Pour through a fine-mesh strainer or nut milk bag into a pitcher, pressing to extract the juice. This gives a silky, light texture.
Chill and serve: Pour over ice and garnish with a mint sprig.
Drink right away for the brightest flavor.