Mix water, sugar and yeast in a small bowl and let rest for 5 minutes.
Mix flour and salt in a bowl. Then add olive oil and the water yeast mixture and knead for 5 minutes until smooth. Cover the dough with a damp towel and leave to rise in a warm place for 60 minutes.
Rub a baking tin with a little olive oil. Spread the dough evenly in it. Cover again with a damp towel and leave to rise for another 30 minutes.
Halve the cherry tomatoes and stone the olives. Use your fingers to press holes evenly into the dough. Spread the cherry tomatoes, olive oil and rosemary over the dough. Leave to rise for another 60 minutes. Then spread the olive oil over the dough.
Preheat oven to 200°C.
Bake the focaccia for 20 minutes.