Heat oil in a large Dutch oven or pot over medium-high heat. Saute scallions, leek, onion and celery until onion is translucent. Cover, reduce heat and cook gently 5 minutes, or until vegetables have released their juices and softened.
Add broth, green beans, potato and zucchini. Simmer, uncovered, 5 minutes. Stir in spinach. Add canned beans. Season to taste with salt and pepper. Cook until beans are heated through, about 5 minutes.
Ladle soup into bowls and serve, topped with some of the cheese. (Soup keeps up to three days if covered and refrigerated.)