Cut each unpeeled orange crosswise into 7 or 8 thin slices, discarding the end pieces and any seeds.
Fill a saute pan or frying pan half full with water and bring to a boil.
Add the orange slices and cook for 1 minute.
Drain and set aside.
In the same pan combine the sugar and the water.
Bring to a boil, stirring to dissolve the sugar completely.
Reduce the heat to medium-low, add the orange slices and gently cook uncovered, turning a couple of times, until tender, about 5 minutes.
Set the slices aside to cool in their liquid.