How to cook/serve Confit de Canard?
Usually it is removed from the fat, and warmed in an oven.  The exact instructions will probably be on the tin, but from memory I think it was about 15 mins @ 180c, as you only really need to warm them through and remove the excess fat.

We have always served it with potatoes roast in some of the fat from the tin.  Usually par-boiled, minced garlic added, then shaken in the boiling pan (with a lid on) to mix the garlic in and to rough up the edges so you get some nice crispy bits, then put into a hot tray of duck fat (go on be generous with the fat, it's delicious) and into a hot oven till crispy.

You could also serve it with dauphinoise potatoes, which would also be great.

Accompanied by french beans or broccoli or some other green veg, and some crusty French bread to mop up the fat with.  mmmm.  Makes me want to go and get my tin out of the cupboard for tonight.