Preheat oven to 425°F. Split dough in half. On a floured surface, roll each half into a ten-inch square. Place each on a greased baking sheet. Build up sides slightly. Prick dough with a fork. Brush with half of the oil.
Bake for 12 minutes, or until lightly browned. Brush again with remaining oil. Arrange plum slices on dough and sprinkle with feta. Bake for 7 to 10 minutes more, or until heated through. Cut each pizza into 6 slices.