Most times when talking about skinning wings you are presented with only 2 choices. Strip the secondaries, or do an underwing incision. There are more ways than that. I want to share with you my preferred way of doing the wings.....secondaries still attached and no incision. This may take a minute or two longer to do while skinning, but the outcome gives me the best quality and the additional time skinning is made up during the mounting / grooming process because you don't have to fight the secondaries. So the first photo shows the wing skinned down to the first joint.
This photo shows how you can work the skin along the top of the wing (radius) back and still leave the secondaries attached to the ulna.
This one shows that by grabbing the skin on either side of the bones, you can create a "pocket" and detach the skin further from the bones and meat.
With the skin worked back you can now cut the ligaments and meat on the open end.
You can now grab the meat and ligaments and pull towards the end of the wing. The ligaments act as a pull string and they help to get into the back corner. When you have the meat down as far as you can, cut it.
Using a modeling tool, pick out the last of the meat and your good to go!
With the secondaries still attached, working the wing is much easier during the mounting process. Hope this helps someone. Enjoy!