Special equipment: a pizza stone and pizza peel or 2 baking sheets
For the pizza dough: Add the warm water in a small bowl and sprinkle over 1 teaspoon of the sugar and the yeast; set aside so the yeast can proof.
Oil two bowls with a little olive oil and set aside.
In the bowl of a stand mixer fitted with a dough attachment, mix together the olive oil, salt, 3 1/2 cups of the flour and the remaining 1 1/2 teaspoons sugar. Stir the yeast in the water to make sure it's all dissolved and add it to the flour mixture. Mix on medium-low speed until everything is combined. Increase the speed to medium and allow the machine to knead the dough, adding more flour if necessary, until it is smooth and comes away from the side of the bowl, 6 to 7 minutes.
Divide the dough in two pieces and roll each into a ball. Place a ball in each of the oiled bowls seam-side down, and brush the tops with a little oil to stop them from drying out. Cover the bowls with plastic wrap and place in a warm place (inside a microwave or a turned-off oven works best) until it doubles in size and when poked with a finger, the indent remains (it doesn't spring back), about 1 1/2 hours.
For the white pizza with prosciutto and arugula: Place a pizza stone in the oven and preheat the oven to 475 degrees F. If you don¿t have a pizza stone you can use a large baking sheet turned upside down.
Using a fine grater, grate the garlic in a small bowl and mix it with the oil; set aside.
Sprinkle some flour onto your counter. Take 1 ball of pizza dough and dredge it in the flour on all sides. (Reserve the remaining ball for another use; store in the refrigerator for up to 24 hours.) Using your hands or a rolling pin, roll the dough out to a 10-inch circle and place it on a semolina-dusted pizza peel or an upside down baking sheet.
Brush the surface of the dough with some of the garlic oil and sprinkle evenly with the shredded scamorza.
Slide the pizza onto the pizza stone or upside down baking sheet. Bake the pizza until the crust is cooked and beginning to brown, about 20 minutes. Remove and top with the ribbons of prosciutto. Pop the pizza back in the oven and bake until the prosciutto heats up just a little bit, about 2 minutes more. Remove from the oven and scatter over some fresh arugula.
You can use store-bought pizza dough instead of homemade. If you can't find scamorza, substitute plain fresh mozzarella cheese--it will still be delicious!