To prepare quinoa salad, place cooked, cooled quinoa into a large mixing bowl. Add half of dressing, stirring to combine. Add green onion, olives, pistachios, peppers, cucumbers, Feta Cheese and Parmesan Cheese. Gently toss to combine. Slowly pour in remaining dressing, stirring to combine. Take a spoon to taste, add kosher salt and freshly ground black pepper as needed. Store in an airtight container, chilled in the refrigerator until ready to serve.