Pre-heat your oven to 240°C, then dust a large baking tray with coarse semolina and roll out the dough to make a 30cm long oblong pizza.
To make dough combine top six ingredients in the ingredients list and leave to rise in a bowl (covered) in a warm place. Once risen, divide into two balls and roll out.
Spread the tomato puree over the base and twist the edge to make the high sides. Spread lightly with one cup of the mozzarella, then place on the sliced cooked potato.
Combine together the olive oil, garlic and chilli slices and brush this mix over the pizza.
Scatter the remaining cheese over the top and place in the hot oven and bake until crisp.
Remove from the oven and top with the smoked salmon and dill sprigs then cut and serve.