Bring water and salt to a boil in a medium saucepan. Add barley; cover, reduce heat, and simmer 10 minutes. Add corn (do not stir), cover, and cook 5 minutes or until barley is tender. Remove from heat, and let stand, covered, 5 minutes.
Transfer barley mixture to a large bowl. Add beans and next 6 ingredients; stir gently. Place lettuce leaves on 5 salad plates; spoon warm mixture onto lettuce leaves. Sprinkle each serving with cheese.