Working with 1 orange at a time, cut a thin slice off the top and the bottom, exposing the flesh. Stand the orange upright and, using a sharp knife, cut off the peel, following the contour of the fruit and removing all the white pith and membrane. Cut the orange crosswise into slices 1/2-inch thick. Transfer to a shallow nonaluminum bowl or dish. Repeat with the remaining oranges. Set aside.
In a small saucepan over medium-high heat, combine the strips of zest with water to cover. Bring to a boil and boil for 1 minute. Drain and immediately plunge the zest into a bowl of cold water. Set aside.
To make the syrup, combine the orange juice and honey in a large saucepan over medium-high heat. Bring to a boil, stirring to dissolve the honey. Reduce the heat to medium-low and simmer, uncovered, until the mixture thickens to a light syrup, about 5 minutes. Drain the orange zest and add to the syrup. Cook until the zest is translucent, 3 to 5 minutes.
Pour the mixture over the oranges. Cover and refrigerate until well chilled, or for up to 3 hours.
To serve, carefully divide the orange slices and syrup among individual plates. Drizzle each serving with 1 1/2 teaspoons of the orange liqueur, if using. Garnish with the mint and serve immediately.