Cook the quinoa by placing in a saucepan with 500ml boiling water and simmering for about 15 minutes until the water is absorbed (or follow the manufacturers instructions as products vary) It should be fluffy but slightly chewy.
Set aside to cool then add the rest of the ingredients, mixing well. Add more oil or lemon juice to balance the flavour depending on the ripeness and sweetness of the tomatoes.
Season well and eat!