1. Remove the ends from the cucumber and slice it in half lengthwise. Scrape the seeds out with a spoon and then chop the cucumber into chunks. Remove the seeds from the bell pepper and also cut it into chunks. Dice the onion. Add the cucumber, bell pepper, onion, and garlic (peeled) to a food processor. Process until the vegetables are minced.
2. Pull the leaves from about ¼ of the parsley and cilantro bunches. Add the leaves to the food processor along with the olive oil and the flesh from the avocado. Purée until smooth.
3. Add the water, one tablespoon of lemon juice, and one teaspoon of salt. Purée until smooth again. Taste the soup and adjust the salt or lemon juice if desired.
Serve immediately or chill until ready to eat.