Combine all ingredients a suitable mixing bowl and mix to make a uniform ball. Remove to a lightly floured work surface and knead by hand for five or six minutes or until the dough becomes smooth and elastic. Cover with a damp towel and allow to rest in a warm place (between 70 and 90 degrees F.) for 30 minutes. Flatten the dough slightly and divide into six equal (about 4-1/2 oz. each) pieces. Roll each piece into a ball, stretching the dough as tightly as possible. Again, cover with a damp cloth and rest for 30 minutes. (You may freeze any doughs that you do not intend to use immediately at this stage or refrigerate overnight to use the next day). To make three pizzas Cut potatoes (or any small waxy type of potato), about 1" in diameter. Start in cold water and bring to a boil. Cook for about 7 minutes. Remove from the water and cool, then peel and slice into 1/4" slices. Cipollini onions (or any small, sweet onion), about 1" in diameter. Peel and saute in 1 Tbl. olive oil until browned on both sides. Add 1 tsp. sugar and 1/4 cup balsamic vinegar to the pan then reduce the heat and summer until the onions become soft. Cool and separate into rings. For each pizza, press a rounded ball of dough, working from the center toward the outside, to make it flat and thin. Leave about 1/2" lip around the edge. Top with the grated fontina followed by the sliced potatoes, onion rings, chopped thyme and grated Parmesan. Bake on a pizza stone in a 500 degree oven for approximately ten minutes or until the edges of the crust become golden brown and the cheese melts and begins to bubble. Toss the arugula leaves in 1 tsp. of virgin olive oil and sprinkle over the pizzas to garnish.