The breasts are the best part of the duck. The French word “magret” is used to describe the duck breast taken from a Mulard or Barbary duck raised for its foie gras. Duck magrets can be cut from a whole duck (before it is jointed) using a boning knife, or can be bought ready-cut. They are not usually skinned. The breasts from non fattened ducks are referred to a duck fillets.
Trim away the rough edges of skin from duck breast. Turn the breast on to its skin and trim away the tendon from the flesh with a boning knife.
Score the skin in a criss-cross pattern being careful not to cut through to the flesh. This makes it more attractive for serving, and helps release fat during cooking.
Find this technique in the Le Cordon Bleu book Complete Cooking Techniques (p 95)