Place all of the ingredients - cucumber, pepper, green onion, avocado, garlic, parsley, mint, lemon juice, olive oil, vinegar, salt and water in a blender. Blend until smooth and everything is well blended. Taste and adjust seasoning to taste, with a little more salt, some pepper or a little more lemon or vinegar as you prefer. If it feels too tart (eg from the pepper), you can add a few green grapes or a shall pinch of sugar to take the edge off. If the texture is too thick for your liking, add a little more cold water and re-blend, and again if needed. Serve immediately or chill a short while first. If serving in bowls, I suggest drizzling with a little olive oil and adding some herbs as garnish (and/or a little diced cucumber).