Prepare quinoa according to the instructions on the packet. Wash the tomatoes, grate dry and cut in half. Drain the corn and beans, rinse with cold water and drain. Peel and finely chop the onion. Halve the peppers, clean, wash and cut into small cubes.
Peel garlic and chop finely. Mix vinegar, sugar, mustard, garlic and onions in a bowl. Fold in the oil in a thin stream. Season with salt and pepper.
Mix quinoa with dressing, corn, beans and paprika. Wash the basil, shake dry and cut into strips, except for a few leaves for garnishing. Fold into the salad. Season salad with salt and pepper.
Arrange in a bowl and garnish with basil.