1. Mix the water, milk and yeast together in a large bowl and stir with a wooden spoon.
2. Add the flour, salt and olive oil. Mix together with a wooden spoon until the dough is too thick and sticky to stir.
3. Spread a little flour on a work surface and place the dough on top of the flour. Knead the dough by pulling the dough from the sides and folding it in the middle. Keep kneading until the dough becomes a smooth ball. If it sticks to the table or to your hands, add a little more flour.
4. Rub a clean bowl with the olive oil and put the dough in it. Cover the bowl with a towel and put it in a warm place. Let the dough rise for about 1 1/2 hours, or until doubled in volume.
5. Punch the raised dough down with your fist. Turn the dough over, form it into a ball again, cover, and let rise for another hour.
6. Heat the oven to 450°F. Roll out the dough with a rolling pin or use your hands to pat the dough into a circle about 12" to 14" across and 1/4"-thick. Place the dough on an oiled baking sheet.
For the topping:
1. Sprinkle the garlic and spread the olive oil over the rolled dough, then sprinkle the tomatoes. Sprinkle the mozzarella cheese, leaving the edge of the pizza free. Place the onions on top of the cheese. If desired, drizzle a little Roasted Garlic Vinaigrette on top of the pizza for added flavor.
2. Bake until nicely browned and crispy, about 15 minutes. Season with salt and pepper. Cut the pizza into 8 slices.