In a saucepan, bring the fennel, water and honey to a boil. Cover and cook over high heat, stirring a few times, until the fennel is crisp-tender, 2 minutes. With tongs, transfer the fennel to a bowl. Add the zest and juice to the saucepan and boil until syrupy, about 2 minutes. Pour the syrup over the fennel and toss. Let cool. Season lightly with salt.