Add quinoa and 2 cups of water to a pot over medium high heat. Bring water to a boil. Cover pot, and reduce heat to low. Allow to steam for about 15 minutes while preparing the other ingredients.
Chop cucumbers, nectarines, tomatoes, and walnuts.
Prepare the dressing by adding all the ingredients to a blender, and processing until it's a vibrant bright green.
Once the quinoa is cooked, fluff with a fork, and set aside to cool.
In a large bowl, add quinoa and arugula, and toss to combine. Top with cucumbers, tomatoes, nectarines, and olives. Gently mix in.
Drizzle dressing over the salad when ready to serve, and garnish with additional herbs, walnuts, and feta cheese.
If not serving this salad right away, don't add arugula. Mix the quinoa, cucumber, tomatoes, olive and nectarine with the dressing, and refrigerate. When ready to serve, stir in arugula, and top with walnuts and feta cheese.