Rinse quinoa in a fine-mesh strainer under cold water for 30 seconds to remove bitterness. Combine quinoa, water, and salt in a medium saucepan. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until water is absorbed and you see the little tails. Remove from heat and let stand covered for 5 minutes. Fluff with a fork and spread on a plate to cool to room temperature, about 10 minutes.

While quinoa cooks, dice the cucumber into small cubes, halve the cherry tomatoes, finely dice the red onion, and chop the parsley. Drain and rinse the chickpeas thoroughly.

In a small bowl, whisk together olive oil, lemon juice, minced garlic, oregano, salt, and pepper until emulsified.

In a large bowl, combine cooled quinoa, chickpeas, cucumber, tomatoes, red onion, and parsley. Pour dressing over top and toss gently to coat everything evenly.

Fold in the crumbled feta. Taste and adjust salt or lemon juice if needed. Serve immediately or refrigerate for up to 3 days.