Bring a large pot with about 3 quarts of water to a boil and salt generously (about 2 tablespoons). Cook pasta according to the package instructions to al dente. Reserve 1 cup of the pasta water before draining. Drain and transfer back to the pot.
While the water comes to a boil and pasta cooks, make the tomato zucchini mixture.
In a large skillet over medium-high heat, add the oil, tomatoes, zucchini, garlic, and ½ teaspoon salt. Stir to mix everything together, then let cook for 15 minutes, stirring every 5 minutes, or until the tomatoes have burst open and the water that cooked out of the tomatoes/zucchini has cooked down into a sauce (use your spoon to help break open the tomatoes to release their juices once they have burst open). Reduce the heat to medium/medium-low towards the end to prevent burning.
In the large pot (with the pasta in it), turn the heat on to medium and pour the mixture in along with ½ cup of reserved water, butter, and remaining ½ teaspoon salt. Toss to coat until the butter is melted and the pasta has absorbed the liquid and looks nice and saucy and glossy, about 1-2 minutes. Add a splash of more pasta water if needed. Taste and season with more salt, if needed.
Serve topped with parmesan and black pepper.