In a small saucepan, bring 2 cups of water to a boil.
Add the quinoa and stir.
Cover with a lid, reduce the heat and simmer for 15 minutes.
Remove from heat and set aside to cool down (to speed this process, transfer the quinoa to a wide, shallow plate).
In a bowl, combine quinoa, vegetables, lemon juice, olive oil, salt, and pepper. Mix well.