I'm not a fan of Zushiya's Thai counterpart, Sawatdee, so when my sister invited me to dinner I chose to order off the sushi restaurant menu. There is the standard avocado and cucumber roll but there is also a futo roll which offers a wider variety of veggies. The roll was satisfactory, though a bit loose in wrapping, but was not interesting in either flavor or appearance. I also ordered the seaweed salad. I can't speak to its authenticity but I did enjoy the textures in this dish.
The portions were neither generous nor extremely stingy, the server forgot my sister's drink but the food came relatively quickly. Take note that sushi options will take longer than options from the Thai menu. The restaurant was full at 6:30 on a Thursday night and we had to wait for a table. Our seat next to the servers' supply table was less than ideal and the noise level was fairly high.
If I want sushi, I'd rather go to Masu for their more extensive veg menu, quality options and ambiance. Yet if my sister invites me to Sawatdee/Zushiya in the future, I will likely order the same exact things, just to avoid being the depression of subpar Thai.
Note: Zushiya also offers Inari, or fried tofu stuffed with rice.