Strip the zest from the oranges with a vegetable peeler, making sure not to peel away any of the white pith. Cut the zest into 1/8-inch shreds with a sharp knife. Place shredded zest in a small saucepan and cover with water. Bring to a boil over low heat. Drain zest, discard cooking water and place zest in a bowl; cover zest with cold water and set aside.
Combine the sugar and the water in a medium saucepan, bring it to a boil and cook the syrup until it thickens slightly about 3 minutes.
While the syrup is cooking, peel the oranges to expose the flesh. Lower the heat on the syrup and cook the oranges 1 or 2 (they should be submerged in the syrup--if not, switch to a smaller saucepan) at a time for 3 to 4 minutes.
Remove the oranges from the syrup with a slotted spoon and place in a serving bowl.
Add the shredded zest to the syrup and cook the zest for two minutes, or until the zest is translucent. Remove the zest from the syrup and scatter over the oranges. Chill the oranges and sprinkle with orange liqueur just before serving.