In a saucepan, bring water and salt to a boil. Add buckwheat groats. Cover saucepan, reduce heat to simmer and cook about 10 minutes or until water is absorbed. Remove lid and let groats cool at least 30 minutes.
In a large bowl add all ingredients. Toss well to combine.
Serve right away or refrigerate overnight. Lightly toss again if refrigerated for more than 2 hours.