Southwestern Barley Salad

Name: Southwestern Barley Salad
Ingredients: 3 cups cooked medium pearl barley; 1 (15 ounce) can black beans, rinsed and drained; 1 1/2 cups frozen corn, thawed; 1 1/2 cups diced, seeded tomato; 1 cup frozen peas, thawed; 1/4 cup minced fresh cilantro or parsley; 1 teaspoon salt; 1/4 teaspoon pepper; 1/2 cup water; 3 tablespoons lemon juice; 1 tablespoon finely chopped onion; 1 tablespoon canola oil; 2 garlic cloves, minced; 8 lettuce leaves; 1 ripe avocado, peeled and sliced; 2 medium tomatoes, cut into wedges