Asuka is tucked away under stores on Yorkville Ave in Yorkville. You go down a few steps and enter an authentic-enough looking Japanese restaurant. The staff is very friendly and we were seated quick enough even though it was the peak of lunch hour and the place was packed with suits.
Although it's in Yorkville, I was surprised that the prices are very reasonable (only slightly more than your hole-in-the-wall Queen W sushi joint).
We sat right up at the sushi bar and the chefs, although working at warp speed to meet the orders, were friendly enough to chat.
Word of caution: If you order the beef teriyaki, it comes on a sizzling hot plate with veggies. PLEASE let the veggies cool down for a while. The steak is at the right temperature to eat but I actually burnt my lip with a piece of broccoli.