Peel and finely grate cucumber (best done in a bowl to collect juice.) Squeeze all of the liquid out (see note below.)
Combine all ingredients and mix well. Chill for several hours before serving. Serve with naan, pita, or other flat bread.
Notes
Don't throw out the cucumber juice! Instead, make a glass of Cucumber Lime/Lemon-Ade! I got this idea from something similar served at the Whole Earth Festival in Davis. Combine 1 part cucumber juice with 2 parts water (still, or sparking if you are in a festive mood) and add lime or lemon juice and sugar to taste. It is quick, tasty, and a good way to get some extra nutrients and hydration.