You should be able to find it at many places.
Many of the Disney buffets have salmon, Boma for instance has always had salmon everytime we went.
Most of the table service restaurants also have salmon (check the menus online, sometimes lunch menu is different than dinner menu), like Chefs de France, Tutto Italia...Raglan Road has salmon on the menu.
Plus there is salmon at some QS places like in Japan they have Teriyaki Salmon, Sunshine Seasons food court in the land had salmon on the menu. CHH was previously mentioned. Cookes of Dublin has a salmon wrap, or you can add salmon to a salad.
If you want to go real high end, Artist Point has an amazing salmon entree.