Place the water, sugar and yeast into a jug and stir to combine. Set aside for 5 minutes or until bubbles appear.
Place flour, salt and olive oil into a bowl, add yeast mixture and mix until well combined.
Turn out onto a lightly floured surface and knead for 5-7 minutes.
Return to a clean lightly oiled bowl and cover with a damp cloth. Set aside for 10-15 minutes or until doubled in size.
Divide dough into two pieces and roll each piece out to a rectangle shape that will fit onto your grill plate.
Preheat a char grill or barbecue over high heat.
Peel and devein the prawns, leaving the tails intact or remove if desired.
Place prawns, lemon, chilli, tomatoes and oil into a bowl. Season with sea salt and pepper and toss to coat. Cook for 2-3 minutes on the char grill turning until tomatoes are charred and prawns are just cooked.
Brush dough with oil and place on char grill. You may need to cook in batches. Cook dough for 2-3 minutes or until charred.
Turn dough and brush with oil, top with the mozzarella, parmesan, prawns and tomatoes. Cook for another 2-3 minutes.
Reduce heat and cook with barbecue lid down or place in a 200ºC oven for another 5-7 minutes or until golden and crisp.
Serve topped with torn fresh radicchio.