Duck feet are plentiful in markets serving a Chinese or Southeast Asian community, and fairly inexpensive. They are cooked whole, particularly for dim sum, but are also very useful for adding body to soup stock. Duck feet are about 6 inches long and weigh 1 ounce each.
Boneless duck feet are also available (see below) and are used mainly in salads.
More on Working with Ducks.
If you are plucking your own ducks, you need to scald the feet and peel off the outer scaly skin. A recommendation from an equipment manufacturer is two separate scalds of one minute each. You must not scald too much or the inner skin will come off with the outer.
Boneless duck feet are easy to find in the Asian markets in Los Angeles
but are relatively expensive (around 2009 US $5.99/pound) due to the
amount of hand work necessary to debone them. See US Patent 5437884 for
a description of of how it can be done.
Boneless duck feet are used in pretty much the same way as boneless
chicken feet, mainly in salads. The main difference is the hard nodules
left at the joints are harder than with chicken, and not so chewable, but
they're very small so just swallow them.