Cook beans in large pot of boiling salted water until crisp-tender, about 4 minutes. Drain well. Heat a heavy large nonstick skillet that has been sprayed with olive oil cooking spray over medium-high heat. Add orange peel, lemon peel, and garlic and stir 1 minute.
Add broth and simmer 1 minute. Add butter and beans. Toss until beans are heated through and sauce coats beans, about 2 minutes. This should leave the beans a crisp-tender texture. If you like your beans less-crisp, add 1/8 cup more broth and cook longer. Season with salt and pepper and serve.