Cook the Quinoa: Rinse the quinoa thoroughly under cold water. In a medium saucepan, combine quinoa and water (or broth). Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes, or until all water is absorbed. Remove from heat and let stand, covered, for 5 minutes. Fluff with a fork and let cool completely.
Prepare the Vegetables: While quinoa cools, dice the cucumber, halve the cherry tomatoes, finely dice the red onion, and halve the Kalamata olives. Chop the fresh parsley and mint.
Make the Dressing: In a small bowl, whisk together the olive oil, lemon juice, red wine vinegar, minced garlic, dried oregano, salt, and pepper until well combined.
Combine Salad Ingredients: In a large mixing bowl, combine the cooled quinoa, rinsed chickpeas, diced cucumber, halved cherry tomatoes, diced red onion, halved Kalamata olives, crumbled feta, chopped parsley, and chopped mint.
Dress the Salad: Pour the lemon-herb dressing over the salad ingredients. Toss gently until all ingredients are evenly coated.
Chill and Serve: For best flavor, cover and refrigerate the salad for at least 30 minutes to allow the flavors to meld. Serve chilled or at room temperature.