Start by prepping the salad dressing. Add all salad dressing ingredients to a large mixing bowl. Whisk well and pour into a Mason-style glass jar. Set aside.
Assemble the salad by adding the cooked quinoa to a serving bowl. Stir in the chickpeas, chopped cucumber, cubed avocado, cherry tomatoes, and parsley. Toss to combine.
Drizzle with the homemade lemon and oregano vinaigrette. Top with crumbled feta cheese, and shredded chicken if using.