For the pizza dough; combine the water and yeast in a jug, stir to combine. Sift flour into a large bowl and add salt, sugar, oil and yeast mixture. Mix to form a soft dough. Turn onto a lightly floured surface and knead for 8-10 minutes or until elastic (alternatively knead with a dough hook in an electric mixer). Cut the dough into four and shape into even rounds.
Lightly grease two large baking trays. Roll each piece of dough out to 18cm round. Place onto trays. Brush lightly with oil, cover with plastic wrap and a tea towel. Set aside for 15 minutes in a warm place to rise. Preheat oven to 220°C fan forced.
Cut some tomatoes in half, leaving the rest whole. Combine oil, garlic and chilli in a large bowl. Add tomatoes and prawns and season. Sprinkle half the mozzarella evenly over the pizza dough and top with tomato and prawn mixture. Bake for 15 minutes, swapping trays over after 10 minutes.
Scatter the remaining cheese over the pizzas and bake for a further 5 minutes. Scatter with rocket, drizzle with balsamic, season and serve.