Heat oven to 400°F. Spray 15x10x1-inch baking pan with nonstick cooking spray. Cook sausage in medium skillet over medium-high heat until browned and no longer pink. Remove sausage from skillet; drain on paper towels.
Remove dough from can; carefully unroll. Cut in half crosswise. Place halves side by side and slightly overlapping in sprayed pan; press edges together to seal. Press slightly to fit in pan.
Top crust with tomato sauce, sausage, potatoes and onions. Bake at 400°F. for 15 minutes.
Sprinkle with cheese; bake an additional 10 to 15 minutes or until crust is deep golden brown.