Ohmuk is fried fish cake. It's also known as "Odeng". It's manufactured in different sizes and shapes. This one here is in sheets. There are some shaped like tubes, hotdogs, and balls. The taste is pretty much consistent and resembling to that of "kikiam", only it's less fishy.
I haven't seen this one in local supermarkets yet but you can get this one in Korean or Japanese grocery stores near you.