Preheat oven to 425°.
Combine tomatoes and water; let stand, covered, 30 minutes. Drain tomatoes; coarsely chop.
Heat 1 tablespoon olive oil in a large nonstick skillet over medium-high heat. Add onion; sauté 5 minutes. Cook 15 minutes or until golden brown, stirring frequently.
Unroll the bread dough, and flatten into a 13-inch circle on a lightly floured surface. Place the dough on a 12-inch pizza pan sprinkled with cornmeal. Crimp edges of dough with fingers to form a rim. Pierce dough with a fork. Bake at 425° for 10 minutes, and set aside.
Combine potatoes and next 5 ingredients (potatoes through salt) in a bowl. Coat a jelly-roll pan with cooking spray; arrange potatoes in a single layer in prepared pan. Bake at 425° for 20 minutes or until potatoes are lightly browned, stirring once.
Spread the tomato purée over crust. Top with potatoes, caramelized onions, and sun-dried tomatoes; sprinkle with cheese. Bake at 425° for 15 minutes or until crust is browned.