Scoop the seeds from the tomatoes into a strainer set over a bowl and press on the seeds to extract as much juice as possible. Coarsely chop the tomatoes and add them to the juice.
Heat the oil in a large skillet until shimmering. Add the onion and cook over moderately high heat, stirring, until softened and just brown, about 5 minutes. Stir in the garlic and cook for 1 minute. Add the tomatoes with their juice and the crushed red pepper. Season with salt and cook, stirring, until thickened, about 20 minutes. Stir in the basil and mint and serve.