1.Make pizza dough. Combine flour, yeast, sugar and salt in medium bowl; make a well in the centre. Stir in oil and enough of the water to mix to a soft dough. Knead dough on floured surface about 10 minutes or until smooth and elastic. Place dough in large oiled bowl, cover; stand in a warm place about 1 hour or until dough doubles in size. Turn dough onto floured surface; knead until smooth.
2.Meanwhile, boil, steam or microwave spinach until wilted; drain. Rinse under cold water; drain. Squeeze out excess water; chop spinach coarsely.
3.Preheat oven to 240°C/475°F. Oil two oven or pizza trays; place in heated oven.
4.Divide dough in half; roll each half on floured surface into 15cm x 40cm (6-inch x 16-inch) rectangle. Place on trays.
5.Combine olives, tomato, oregano, garlic and oil in small bowl; season to taste.
6.Divide spinach between bases; sprinkle with half the cheeses. Top with olive mixture; sprinkle with remaining cheeses.
7.Bake pizzas about 15 minutes or until bases are browned and crisp. Cut each pizza into 8 slices.