Spread peanut butter evenly over 3 of the tortillas. Top with strawberry and banana slices. Place remaining tortillas over fruit; press down.
Heat large skillet over medium heat until hot. Lightly spray top of 1 quesadilla with nonstick cooking spray. Place sprayed side down in hot skillet; cook 2 to 4 minutes or until lightly browned.
Spray top of quesadilla with cooking spray. Turn quesadilla; cook an additional 2 to 4 minutes or until lightly browned and filling is thoroughly heated. Repeat with remaining quesadillas. Cut into wedges.