Chilled Avocado-Cucumber Soup

I made this last night for Emilio's going-away-to-New-Zealand-dinner. I'm as green as this soup with envy but we never skip an occasion for a celebratory dinner, so we cracked open some champagne and had a private dinner party. This is a great, fresh, summery soup. There are many different versions of this recipe, most commonly flavored with cilantro. Due to difficulty of locating cilantro here, I improvised with mint and basil which gave it an unexpected and refreshing flavor.

soup ingredients:
* 4 cucumbers, peeled, diced and de-seeded
* 2 avocados, pitted and diced (save some for garnish, if desired)
* 1/4 cup coarsely chopped italian parsley
* 1 green onion, coarsely chopped
* 1 clove garlic, crushed
* lime juice from 2 limes or more, to taste
* 1 cup nonfat plain yogurt
* 1 cup cold water
* salt & pepper
* 1/2 cup diced red tomato to garnish
for the mint-basil oil:
* fresh mint leaves (about 2 tablespoons, finely diced)
* fresh basil leaves (about 2 tablespoons, finely diced)
* salt & pepper
* 1/2 cup high quality extra-virgin olive oil

Combine the first 6 ingredients in a food processor, and process until smooth. Add the yogurt and continue processing, then begin slowly pouring in the water while processing until you reach the desired consistency. Add salt and pepper to taste.
Refrigerate for at least 30 minutes.
Whisk together the ingredients for the mint-basil oil.
Spoon the soup in to bowls and drizzle with the oil. Garnish with tomato, avocado and a slice of lime, if desired.