There are some good fresh fish restaurants along Ilsan beach. You can even sit outside of the 7-11 and drink..or on the beach if you prefer.
Regarding the Turkish and Mexican places....It took me awhile to find them. They are in Dong-gu area which is where the shipyards are. Let me see if I can find a website.
There is a map at the bottom.
Ulsan's Restaurant Guide » White House Traditional Turkish Restaurant
Ulsanonline has a ton of information in regards to living in Ulsan.
Here is some information on the Mexican place. There should be a map on there as well. As any other foreigner and they should know it. It is along the water as well.
Ulsan's Restaurant Guide » O’Taco: Oh My Gawt! It’s Finally Here!