Place sliced cucumber in a large bowl. Toss with sea salt, vinegar and honey, and marinate for at least one hour, or up to three. The salt should draw liquid, which will aid with pureeing (alternatively, you could have a shorter marinating time and use more water for blending, but I expect this will dilute the flavor).

Peel and pit the avocado and add to a blender along with the cucumber mixture (and all of the liquid that’s been released), the chopped garlic, jalapeño and the lime juice (start with a tablespoon and add more later to suit your taste). Add a generous pinch of sea salt. Puree until very smooth, about 2 minutes, adding filtered water to facilitate blending until desired consistency is achieved (not as thick as baby food, but more viscous than juice).Taste and adjust seasoning as necessary.

Chill until ready to serve. Divide soup amongst chilled bowls, garnish with chopped cucumber and a sprinkling of cilantro.