Cut the cucumbers in chunks. Blend together the cucumber chunks, garlic paste, mint leaves, yogurt, lime juice, and honey till smooth. Add the water and blend again.
Season with salt, pepper and a little more lime juice if necessary. Chill until ready to serve. Stir well before serving, and ladle into bowls. Garnish with a little finely chopped onion, walnuts and a sprig of mint.
Serve with crisp plain or herbed flatbreads.