Line baking sheet with parchment paper and set aside.
Wash the oranges well. Cut into ⅛ to ⅙ inch (3-4mm) thick slices with a serrated knife or sharp (chef's) knife, or a mandoline slicer. If there are seeds, remove them gently.
Place the orange slices in a pan and cover with enough water and bring to a boil over medium heat. Reduce the heat to medium-low and let it simmer for 2 minutes. Once it starts to simmer, prepare the ice old water by filling a large bowl with cold water and ice. As 2 minutes pass, remove the slices with a slotted spoon and put them into ice-cold water.
Place the sugar and water in a large pan and put it over med-low heat and stir until the sugar dissolves.
Once the sugar dissolves, add the orange slices. Without stirring, let the slices simmer at medium-low heat for almost 40 minutes or until they are almost translucent. You'll notice many mini bubbles on top of the slices when they are candied.
Using tongs, remove the slices from the pan and let the excess syrup drip off back into the pan. Place the slices on a baking sheet that is lined with parchment paper. Dry them at 200°F(95C°) for 1 hour to 1 hour 15 minutes. If you like, you can dry them uncovered at room temperature; it takes almost 24 hours to dry. They will be a little sticky to the touch which you should expect after they are dried. (You can use the leftover syrup to flavor your tea or use it to flavor yogurt, etc)
You can enjoy them as they are or dip them into chocolate or coat them with sugar.