1 Rinse lemon in hot water, wipe dry and finely zest. Juice lemon.
2 Rinse zucchini and coarsely grate on the large holes of a box grater. Sprinkle with salt and let stand for 10 minutes.
3 Transfer zucchini to a towel and squeeze out excess liquid, discarding the liquid. In a bowl, combine grated zucchini with lemon zest, 2 tablespoons olive oil and 1-2 tablespoons lemon juice. Season with pepper.
4 Peel and chop garlic. Rinse marjoram, remove leaves from stems and chop leaves. In a small bowl, mix garlic and marjoram with the remaining olive oil.
5 Divide pizza dough into eight pieces. On a floured work surface, roll out pieces into rounds, each 1 cm (approximately 3/8-inch) thick. If using store-bought dough, prepare according to package instructions.
6 Transfer 4 dough rounds to a floured baking sheet. Sprinkle each with about 1 tablespoon marjoram and garlic oil.
7 Divide zucchini over the pizzas.
8 Drain mozzarella, cut into small pieces and layer on top of the zucchini. Place baking sheet on the lowest level of a preheated oven at 230°C (fan 200°C, gas mark 3-4) (approximately 450°F/convection 400°F). Bake 20-25 minutes. (Bake in two batches, if necessary). Sprinkle with a pinch of marjoram before serving.