In a small bowl, dissolve the yeast and sugar in warm water. Let it sit for about 5-10 minutes until frothy.
In a large mixing bowl, combine the flour and salt. Create a well in the centre and add the yeast mixture and olive oil.
Mix until a dough forms, then knead on a floured surface for about 5-7 minutes until smooth and elastic.
Place the dough in a lightly oiled bowl, cover with a damp cloth, and let it rise in a warm place for about 1 hour, or until doubled in size.
Preheat the oven to 220°C.
Once the dough has risen, punch it down and transfer it to a greased baking tray (about 12x16 inches).
Gently stretch and spread the dough to fit the tray.
Press the halved cherry tomatoes into the dough, drizzle with olive oil, and sprinkle with sea salt and fresh rosemary.
Cover the tray with a cloth and let it rise for another 30 minutes.
Bake in the preheated oven for 20-25 minutes, or until golden brown.
Remove from the oven, let it cool slightly, and cut into squares.