Heat the olive oil over medium heat in a large, heavy soup pot and add the onion, carrot, and celery and a pinch of salt. Cook, stirring often, until the vegetables are tender, about 8 minutes. Add the garlic and cook, stirring, until fragrant, about 30 seconds. Stir in the tomatoes and juice from the can, add another pinch of salt and cook, stirring often, for 5 to 10 minutes, until the tomatoes have cooked down slightly.