As much as possible, I try to train my kunekunes to be tolerant of hoof trimming while laying down for belly rubs. I do this simply by handling their feet and individual toes a lot while giving belly rubs. It makes it a pleasant experience for them, even if I can only do a foot at a time.
However, there are some kunekunes that are "wise to these tricks" and need a different approach. I try to avoid sedation in my pigs as much as possible as pigs are more prone to complications during sedations (ie tracheal spasms resulting in cessation of breathing). Flipping pigs is our alternative. It takes a couple of strong people and quick reflexes to catch them off guard, but once they are in the proper position, its possible to hold and trim with little trouble. It doesn't hurt them and allows the job to be done quickly and with as little stress as possible.
We hope you find this video useful, it shows the flipping procedure as well as where, and where not to cut. This is another one of those tasks that I complete 1-2 times per year but the needs vary depending on the foot structure of the pig and the terrain.