There is always a jar of candied citrus peel and ginger in our house to accompany an espresso or a bar of dark chocolate after a meal. When we have a huge variety of citrus on hand - or are making lots of juice - we save the peels to candy.
Julienne the peel and soak in water over night to release any bitterness (changing the water once). Then bring a simple syrup of one part water to one part sugar to a boil and boil to the soft-ball stage. (We used two cups sugar to two cups water for 10 fruit peels. And we assessed the soft-ball stage by keeping a glass of ice-water on hand - dripping the boiling syrup in occasionally until it formed a soft ball in the ice-water.)
Then macerate the peels in the simple syrup for a few hours before straining and distributing them on a drying rack. Sprinkle with Demarra sugar and let dry for about half an hour before storing in an air tight container.