Step 1: Rinse quinoa: Place the quinoa in a fine-mesh sieve and rinse thoroughly under cold running water for at least 30 seconds to remove any bitterness.
Step 2: Cook quinoa: In a medium saucepan, combine the rinsed quinoa and 2 cups of water or vegetable broth. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes, or until all the liquid is absorbed. Remove from heat and let stand, covered, for 5 minutes. Fluff with a fork and spread it out on a baking sheet to cool completely.
Step 3: Prepare vegetables: While the quinoa cools, dice the cucumber, red bell pepper, and red onion. Halve the cherry tomatoes. Chop the fresh parsley and mint.
Step 4: Make dressing: In a small bowl, whisk together the extra virgin olive oil, lemon juice, minced garlic, dried oregano, salt, and black pepper until well combined.
Step 5: Combine ingredients: In a large mixing bowl, combine the cooled quinoa, diced cucumber, red bell pepper, cherry tomatoes, red onion, rinsed chickpeas, crumbled feta cheese, chopped parsley, and chopped mint.
Step 6: Dress the salad: Pour the prepared lemon-herb dressing over the salad ingredients. Toss gently until everything is well combined and coated with the dressing.
Step 7: Chill and serve: For best flavor, cover the salad and refrigerate for at least 30 minutes, or ideally 2-3 hours, to allow the flavors to meld. Serve chilled.