Combine Balsamic Dressing with mushrooms in a large heavy-duty zip-top plastic bag. Seal, and marinate mushroom mixture in refrigerator 1-8 hours. Remove mushrooms from bag, reserving Balsamic Dressing.
Place mushrooms on broiler pan coated with cooking spray, and broil 7 minutes or until browned. Combine mushrooms, reserved marinade, and beans in a bowl; toss gently.
Place 2 cups salad greens on each of 4 plates. Spoon 1 1/2 cups mushroom mixture over each salad, and top each with 1 teaspoon toasted pine nuts.