Bring water to a boil; stir in barley, bouillon granules, and 1/4 teaspoon salt. Reduce heat. Cover; simmer 50 to 60 minutes or until tender, stirring occasionally. Drain; cool. Combine cooked barley, chicken, grapes, celery and walnuts. Combine remaining 1/4 teaspoon salt with remaining ingredients; mix well. Pour over barley mixture, tossing lightly. Cover; chill. Serve in cantaloupe halves or on lettuce leaves, if desired. Seven 1 Cup Servings *NOTE: To substitute 2/3 cup Quaker Scotch Brand Quick Pearled Barley, decrease water to 2 cups and cooking time to 10 to 12 minutes. Proceed as recipe directs. NUTRITIONAL ANALYSIS per serving: * calories 351 * carbohydrates 21 g * protein 15 g * fat 23 g * calcium 33 mg * sodium 380 mg * cholesterol 50 mg * dietary fiber 3 g