My first pick would be Wafu (which is not a sushi restaurant, though there are a few raw choices on the menu) - the food there is excellent, including the ramen, good drinking choices, great service. Sake can be a bit expensive there, but it is a very good list.
Hokusei is a sushi restaurant, but the quality of the fish and the selection, in addition to the great execution, keeps me coming back. They opened in late April, and are just starting to hit their stride, IMO. Monday is a crowded all day happy hour (great discounts on good stuff), but Sunday should be a bit mellower. I always sit at the sushi bar and ask Cody what's good and chat with him while he works. Another good sake list, nice cocktails too.
Riffle is new, but the reports have been good. They are actually a fish/seafood focused place. This one is on the west side.
We are not a city with with many "seafood restaurants" yet so many of our great restaurants do wonderful things with fish.
I did not chack to make sure these are all open on Sunday nights, so please do so before you go! ;o)
I have been to RIffle twice now and immensely enjoyed it both time. Nice variety of sea food options form the raw bar, on the appetizer/salad front, and entrees. All well prepared and tasy.
Persona faves have been, salmon carpaccio, tuna salad, halibut cheeks and whole fish branzino, I also very much enjoyed the brussel sprout salad and side as well. Easy bus to The Pearl district or cab of about $10.
It is not cheap s it is al la carte. Our group liked that you can order a few side and salads to share then each our own main.