Deli Beef and Bean Salad

1  bag (10 ounces) mixed salad greens                        

1 pint (2 cups) deli three-bean salad or 1 can (15 to 17 ounces) three-bean salad, chilled                        

1/4 pound cooked deli roast beef, cut into julienne strips (3/4 cup)                        

1 cup shredded Cheddar or Swiss cheese (4 ounces)                        

12 cherry tomatoes, cut in half