Via HappyCow we found out that you can get vegan sushi at Banzai Sushi Bar.
We went there one year ago and still remember it.
The menu markes vegan dishes (They have a vegan salad too).
The avocado makis are really, really good!
$1 each maki isn't low priced but worth it!
Unfortunately they don't have much vegan stuff.
Cons: limited vegan selection