1Spray large cookie sheet with cooking spray; sprinkle with 1 tablespoon cornmeal. In 2-quart saucepan, mix 1 cup cornmeal and 3/4 cup water. Stir in 3 1/4 cups boiling water and 1 1/2 teaspoons salt. Cook over medium heat about 4 minutes, stirring constantly, until mixture thickens and boils.
2Reduce heat. Cover; simmer about 10 minutes, stirring occasionally, until very thick. Remove from heat. Stir in olive oil until smooth. Spread hot polenta in 11-inch round on cookie sheet. Cover with plastic wrap; refrigerate at least 1 hour or until very firm.
3Meanwhile, in 10-inch nonstick skillet, melt butter over medium heat. Add onion and sugar; cook 15 to 20 minutes, stirring frequently, until deep golden brown and caramelized. In 7-inch skillet, cook potatoes in hot vegetable oil as directed on package; season with 1/8 teaspoon salt and the pepper.
4Heat oven to 450°F. Bake crust 20 minutes. Spread pizza sauce over crust; spoon caramelized onions evenly over sauce. Top with potatoes and cheese. Bake 8 to 10 minutes longer or until cheese is melted and potatoes are tender. Sprinkle with oregano.