Rinse the quinoa thoroughly and soak it in water for 15 minutes.
Bring water to a boil in a pot, add the quinoa, and cook for 15 minutes, then drain the water.
Cut cherry tomatoes, cucumber, and onion into bite-sized pieces.
Place the cooked quinoa and chopped vegetables in a bowl.
Add olive oil, lemon juice, salt, and pepper, and mix well.
Serve in a dish to finish.