Heat oven to 350°F. Spray large cookie sheet with cooking spray. Unroll both cans of dough into 2 large rectangles on cookie sheet. Place rectangles with long sides together, forming 15x10-inch rectangle; press edges and perforations to seal.
In medium bowl, mix chicken and buffalo wing sauce. Spoon chicken mixture lengthwise in 4-inch-wide strip down center of dough to within 1 inch of short sides. Top with mozzarella and blue cheeses, bell pepper and onion.
Bring long sides of dough up over filling, overlapping 1 inch; firmly press center seam and with fork, press ends to seal.
Bake 30 to 40 minutes or until deep golden brown. Immediately remove from cookie sheet. Cut crosswise into slices; serve warm with salad dressing.