Prepare pizza crust according to package directions. Divide dough into 2 portions.
On lightly floured work surface, roll out each portion into large rectangle, about 1/4 inch (5 mm) thick. Using pizza cutter or knife, carefully cut each rectangle to form an upside-down “U” shape to resemble the silhouette of a rainbow. Transfer pizzas to 2 parchment paper–lined baking sheets.
Spread sauce over dough in circular motion to edges of crust. Sprinkle with mozzarella. Arrange rows of cherry tomatoes, orange pepper, corn, broccoli and red onion over top to resemble colours of a rainbow.
Bake according to package directions. Let cool for 5 minutes before serving. Cut slices crosswise, so that each serving includes each colour of the rainbow.