1. Pick over beans and discard any broken ones and foreign objects. Rinse and place in a large saucepan. Add bay leaf and water to cover by 2 inches. Bring to a boil. Turn down heat and cook at a steady simmer for 1 to 1 1/2 hours. The cooking time will vary according to the age of the beans. Toward the end of the cooking time, add salt to taste. Let cool in liquid; drain when cool, and discard bay leaf.

2. Place rice in a 2-quart saucepan with a tight-fitting lid. Add 3 1/2 cups water and 1 teaspoon salt. Bring to a boil. Turn down to a simmer, cover, and cook for 20 minutes. Remove from heat and let stand, covered, for 10 minutes. Fluff with a fork and transfer to a bowl

3. Cut cucumber and celery into 1/4-inch dice. Add to rice along with beans and scallions. Toss with vinaigrette. Serve at room temperature within a few hours.