Mix all ingredients together in a large bowl. Can be served immediately, but it tastes best if it sits in the fridge for at least an hour before serving.
Notes
Leftover quinoa works great in this recipe. If you're making some for another meal, make a little extra to save for this salad. If using a garden cucumber (as opposed to and English cuc), peel then cut in half lengthwise and remove seeds with a spoon.