On a lightly greased baking sheet, gently roll out the crescent sheet to make a rectangle, lightly pressing the dough to shape as needed. Trim away the edges of the dough to form a rainbow, and gently press down the corners so that they do not flare up during baking.
Bake for 8-12 minutes, until lightly golden and crispy. Remove and let cool to room temperature.
While the pizza bakes, prepare the fruit. Cut tops off of strawberries and slice thinly; rinse mandarin oranges and pat dry; peel and slice kiwis into coins, then slice coins in half crosswise to form half-moons. Simply wash and pat dry the blueberries and blackberries. Set fruit aside.
Spread the yogurt over the top of the cooled crust, leaving a 1/2-inch border around all sides. Arrange the strawberries along the outermost edge, “point” down to form the first rainbow stripe. Follow with a “stripe” of oranges, then kiwis, then blueberries, ending with the blackberries as the lower-most stripe. Serve immediately or refrigerate for up to a few hours. Slice and serve.
TO STORE: Rainbow fruit pizza may be stored for several hours in the fridge, covered with plastic, before serving. Once served, the fruit pizza should be consumed within a few hours for best taste.