In a small bowl, combine the tarragon, rosemary, lemon zest and orange zest. Season the gremolata with salt and pepper.
In a large skillet, cook the garlic in the butter over moderately high heat until just fragrant, about 1 minute. Add the beans, toss to coat and cook for 2 minutes. Add the chicken broth, cover tightly and bring to a boil. Cook until the beans are crisp-tender, about 3 minutes. Remove the lid and cook, tossing occasionally, until the broth is nearly evaporated and the beans are tender, about 4 minutes longer. For Kids Transfer half of the beans to a bowl and season with salt and pepper. For Adults Add the gremolata to the beans in the skillet and toss until fragrant. Stir in the orange and lemon juices and transfer the green beans to a bowl. Serve right away.