Java Sushi (www.javasushitahoe.com) has an extensive listing of Vegetarian-Specific maki rolls.
They have a fun environment with outstanding quality food (and fish...if you do eat fish.) If you are vegan be sure to specify that you want your rolls dairy/egg free since many of their sauces contain egg or whey.
For best service try to get seated at the bar. The service can be a little slow sometimes however it is ALWAYS worth the wait. It is best to get there for an early dinner (5-6PM) or a late lunch (1:30-2:30 PM) to avoid the crowds. Unfortunately it is no secret that they are one of the best restaurants in Truckee (or Lake Tahoe.)
They have a great all you can eat lunch deal. While I don't think that their veg. rolls are on the A.Y.C.E. menu, They are pretty accommodating and would probably let you order them anyways.