Wash the mint and parsley, remove stems and discard.
In a blender, combine olive oil, lemon zest/juice, vinegar, garlic, herbs and pepper. Blend until smooth. Set aside.
Add cauliflower florets to food processor and pulse until the cauliflower resembles small rice or couscous. You may have to process it in batches.
In a medium bowl, combine the tomatoes, green onion, cucumber and cauliflower. Toss gently.
Serve immediately or cover and chill until ready to serve, up to one night.