Grab the spinach and toss it in a blender. Add in the ice cubes, coconut milk (from a carton), liquid stevia, xanthan gum, and MCT oil. Peel and cube the cucumber, adding it in as well.
Blend for 1–2 minutes or until the ingredients are well combined. There may still be little bits of spinach floating around, but these really can't be detected in the texture.
Pour into a nice big glass and savor the refreshingly sweet taste!