Rinse the quinoa. Place quinoa in a fine-mesh sieve and rinse under cold water for 30 seconds.
This removes any bitterness.
Cook the quinoa. Combine 1 cup quinoa and 2 cups water (or broth) in a small pot. Bring to a boil, then reduce heat, cover, and simmer for 15 minutes. Turn off heat and let sit, covered, for 5 minutes.
Fluff and cool. Uncover, fluff with a fork, and spread on a plate or baking sheet to cool faster.
You want it at least room temp before mixing.
Chop the vegetables. Halve tomatoes, dice cucumber and bell pepper, and finely chop red onion. Slice olives and crumble feta. Chop herbs.
Make the dressing. In a jar or bowl, whisk together olive oil, lemon zest, lemon juice, garlic, Dijon, oregano, a pinch of salt, and pepper until emulsified.
Combine the salad. In a large bowl, add cooled quinoa, tomatoes, cucumber, bell pepper, red onion, olives, herbs, and chickpeas if using.
Dress and toss. Pour on the dressing and toss gently to coat.
Add feta last and fold in so it stays a bit chunky.
Taste and adjust. Add more lemon, salt, or pepper as needed. If it tastes flat, a pinch of salt usually wakes it up.
Rest (optional but great). Let the salad sit 15–20 minutes before serving so flavors meld.