To make the broth, put all the duck bits into a large stock pot, cover with water and bring to a boil. Skim the scum that rises to the top, then turn the heat down to a simmer. Do not let it boil from here on in.
While the water is coming to a boil, toast in a dry frying pan the coriander, cloves, fennel seed, cardamom and star anise until fragrant. Stir often to keep from burning.
Once the water in the stockpot is pretty much scum-free, add the onion, ginger, spices, fish sauce, sugar and salt and stir well. Move the pot off the center of the burner a little and simmer for at least 2 hours — I do three hours. Moving the pot off to the side a little allows you to periodically skim the top. You want to get most of the fat off the top.
Once the broth begins to taste yummy, turn off the heat and discard all the duck bits, onion, etc. Then strain the broth through a piece of cheesecloth set in a fine-meshed sieve. Pour slowly and discard the last dregs of the broth, which will have sediment in it.
If you want to be fancy, cool the broth now and once it has been refrigerated for a while, pick off the fat cap that may form.
To serve, heat the broth — do not let it boil — with the 4-inch piece of ginger and the sliced onions. Let this heat through until the onions are wilty, about 10 minutes.
Set out an array of condiments: Herbs, bean sprouts, sliced chiles, fish sauce, hot sauce and hoisin sauce. This is traditional, although you can improvise if needed. The one thing you must have is fresh herbs, however.
Boil water, salt it, and cook the noodles. Traditional pho noodles (available at Asian stores) are best, but I also like Japanese buckwheat noodles, which, while untraditional, taste perfect with the gaminess of wild duck.
Put 2 tablespoons sesame oil in a pan and get it hot. Sear the duck breasts on all sides under a very hot fire — you want a nice sear on the edges but for the duck to still be raw inside. You need not do this, but the seared edges add something to the dish.
When the noodles are done, gather up portions and put them in serving bowls.
Slice the duck breast as thin as you can and lay them on the noodles.
Pick out the ginger from the broth, then pour some broth over the noodles and duck. Be sure to give everyone some onions. Serve at once. Let everyone add whatever condiments they want.