Wash, dry and chop the tomatoes. Season with salt and place them in a pasta strainer. Divide the dough into two portions, one larger than the other. Roll out the larger one into a disk on a floured work surface. Grease a 20 inch pizza pan with oil and place the dough on top. Place the mozzarella slices on top, slightly overlapping. Sprinkle with a little salt and pepper and the chopped basil. Roll out the remaining dough and place on top. Seal around the edges. Drizzle with oil and then place the chopped tomatoes on top. Drizzle the tomatoes with a little oil as well and sprinkle with oregano. Bake in a 500° F over for 20 to 25 minutes. Serve hot.