Rinse quinoa in a fine mesh strainer for 30 seconds. Combine with water or broth in a saucepan, bring to a boil, reduce heat to low, cover, and simmer for 12-15 minutes until liquid is absorbed. Let sit covered for 5 minutes, then fluff with a fork.
Spread the cooked quinoa on a plate or baking sheet to cool for 10-15 minutes. This prevents the salad from becoming mushy.
While quinoa cooks, drain and rinse chickpeas, then pat them dry. Dice cucumber, halve tomatoes, dice bell pepper, finely dice onion, halve olives, and chop herbs.
In a small bowl or jar, combine olive oil, lemon juice, minced garlic, oregano, salt, and pepper. Whisk or shake until well combined and slightly thickened.
Transfer cooled quinoa to a large bowl. Add chickpeas, cucumber, tomatoes, bell pepper, onion, olives, parsley, and dill. Pour dressing over and toss gently.
Sprinkle crumbled feta over the salad and toss gently one final time. Taste and adjust seasoning. Refrigerate for at least 30 minutes before serving to allow flavors to meld.