1/2 cup sour cream
1 lime, quartered
Chilled tequila (optional)
Skin, halve, and stone avocadoes. Roughly chop cucumber, pepper, chili, onion and garlic; put them in blender (or vegetable juicer, if available) with the water and process thoroughly. Strain, pressing well to extract all the juices. Return strained liquid to blender with avocado flesh, cilantro leaves (leaving a few for decoration), lime juice and salt. Process to puree, adjust seasoning.
Serve chilled, topped with a dollop of sour cream, lime quarters and kosher salt. Accompany with small glasses of tequila, either to sip with lime and salt, or to stir directly into the soup (optional).