In a cold pan, add a tiny bit of oil or duck fat, put the heat on medium, and lay the duck breast in the pan, skin side down (apparently, this helps the fat to render better). It should soon start to give a bacon-like sizzle. Let it cook until brown, crisp, and the fat has rendered -- for me, this was about five minutes. Then turn it over and cook the meat side, for about two minutes or so.