Place a large skillet over medium heat and add in the olive oil. Once the oil heats, add in the garlic and cook for 30 seconds or until fragrant.Add in the onions and cook for 2 minutes or until onions are translucent.Add in the crushed tomatoes and season with salt. Lower to a simmer, cook for 5 minutes and then add in the basil.Let the sauce cook for another 5-10 minutes or until most of the liquid has evaporated and it is thicker, suitable for cooking with zucchini noodles.Use with zucchini noodles or freeze to store for future use.