Add the yeast and sugar to the warm water and set aside for 5 minutes. Add the flour and tsp of salt to a large bowl and make a well in the middle.
Pour the yeasty water with 1/2 tbsp of olive oil to the flour and mix until it starts to form a dough. Lightly dust a clean work surface with flour and knead the dough for 10 minutes. When you lightly press your finger on the dough it should spring back up, that's when you know it's ready. It should be smooth and soft.
Shape the dough into a ball then place in a large bowl that's lightly oiled in olive oil. Rub the top of the dough very lightly with olive oil and then cover the bowl with clingfilm or a damp tea towel. Store in a warm place for 1 hour or preferably for around 3 hours until it's doubled in size.
Preheat the oven to 220°C/425F/gas mark 7. Very thinly slice the zucchini and cut the tomatoes in half. Knock back the dough and place on a lined baking tray. Press the foccacia with your fingers to flatten it out onto the tray creating small dimples as you go. drizzle with 1/2 tbsp olive oil and rub all over.
Arrange the slices of zucchini and tomatoes all over the focaccia, pressing the tomatoes in slightly. drizzle again with a little olive oil and rub over the vegetables.
Bake for 10-15 minutes until golden brown around the edges, sprinkle with a little salt and pepper and let it rest for 5 minutes before cutting into slices.
Please note this recipe was tested and developed using metric measurements all imperial measurements are approximate.