1. Rinse the quinoa under cold water.
2. In a saucepan, bring the water to a boil. Add the quinoa, reduce the heat to low, cover, and simmer for 15 minutes.
3. Remove from heat and let it sit, covered, for 5 minutes. Fluff with a fork and let it cool.
4. In a large mixing bowl, combine the cooled quinoa, parsley, mint, tomatoes, cucumber, and red onion.
5. In a small bowl, whisk together the olive oil, lemon juice, salt, and black pepper.
6. Pour the dressing over the quinoa mixture and toss to combine.
7. Serve chilled or at room temperature.