Rinse quinoa under cold water.
In a pot, bring water to a boil. Add quinoa, reduce heat, cover, and simmer for 15 minutes.
Remove from heat and let sit for 5 minutes, then fluff with a fork.
In a large bowl, combine cooked quinoa, cherry tomatoes, cucumber, red onion, olives, parsley, and mint.
In a small bowl, whisk together lemon juice, olive oil, salt, and pepper.
Pour dressing over quinoa mixture and toss to combine.