Heat oven to 400°F. Cut loaf of bread in half horizontally; cut each half crosswise into thirds. Place cut sides up on ungreased large cookie sheet; brush with oil. Bake 5 to 6 minutes or until tops are slightly toasted. Remove from oven.
Spread pizza sauce evenly over cut sides of each piece of bread. Top evenly with ham, onion, nuts and spinach. Place 4 half slices of cheese on top of each.
Bake 7 to 10 minutes or until cheese is melted and pizza is hot.