Heat the water to boiling in a 2-quart saucepan and add the quinoa. Lower the heat to medium-low and cover. Cook until the liquid is absorbed, 15 to 20 minutes. Remove from the heat and cool.
When the quinoa has cooled, add the remaining ingredients. Taste and adjust the seasonings if necessary. You can serve it right away, but it's better to let the flavors marry in the refrigerator for a few hours.