Add the chopped tomatoes, olive oil, lemon juice, salt, sugar, several twists of freshly ground black pepper and the pressed garlic to the bowl. Mix well. Let the mixture marinate while you cook the pasta.
Core and coarsely chop two-thirds of the tomatoes. Halve the remaining tomatoes down the middle and discard the tough top part where the tomatoes met the stem, if it exists. Rub the cut sides of the tomatoes against the large holes of a box grater set in a large bowl. Leave the tomato pulp in the bowl and discard the skin.