Q. How do you use a duck confit? I would like to put it in a
risotto or something like that for a rich flavor.
There are all kinds of traditional uses for the preserved meat of a confit. The most basic is to eat it on its own, hot or cold, and accompanied by mushrooms, fried potatoes, peas and cured ham (such as prosciutto or Bayonne), white beans, cabbage, or lentils, or with a salad of dandelion greens, endive, or white cabbage. The meat has also long been used in parts of France in the thick soups/stews known as garbures and in white-bean cassoulets.
Madeleine Kamman, author of The New Making of a Cook (Canada, UK), says because confits tend to be salty, they are best served with something sour or sweet and sour, which is able to "temper" the saltiness, such as a salad. In her book, she has recipes for a rabbit confit served on a bittersweet salad (with beets, endive, chicory, and escarole) and a duck confit on an orange and tomato compote.
Now with that in mind, you can pretty much do what you want. You can certainly add duck confit to a risotto, where the blandness of the rice will also temper the saltiness of the confit (a low-salt stock would be advisable for the risotto). Beyond the saltiness, though, a confit tends to have a delicate flavor, so avoid burying it in strong dishes that will overwhelm the taste of the meat.