Rinse the quinoa in a fine mesh strainer under cold water for 1-2 minutes.
Transfer the quinoa to a medium saucepan and add 2 cups of water. Bring to a boil, reduce heat to low, cover with a lid and simmer for 15 minutes until all the water has been absorbed.
Remove from heat and fluff with a fork. Allow to cool slightly.
In a large bowl, combine the cooked quinoa, red onion, bell pepper, cucumber and parsley.
In a small bowl whisk together olive oil, lemon juice, salt and pepper. Pour over the quinoa mixture and toss to combine.