Japanese food is a fantastic, yet not an initial obvious option for vegetarians and vegans. Even a japanese steak house (the really fun ones where the hibachi chef cooks your dinner in front of you) can offer an excellent vegetarian meal. If you do not have an aversion to certain vegetables I always say leave it up to the chef because you will most likely get the freshest ingredients and it allows them to be creative with what they love to do, which applies to almost all chefs.
A sushi bar is an excellent option as well. They usually have a veggie combo roll that might include carrot, cucumber, avocado and asparagus, or rolls with single vegetables. I am referring to the rolls made with Nori (edible seaweed) and sticky rice. If you haven’t tried that yet, please do. But there are other things as well, like tempura (fried vegetables). I say go with the new and exciting. However, plain vegetable tempura will not at all satisfy any craving you may have for traditional restaurant fried food. It might just make you feel unhealthy. The veggies used are sometimes really big and great all on their own that frying them seems a shame. Sushi bar’s tend to be a perfect environment where you can try a number of different creations even in the veggie world so be adventurous.
Sushi One is a highly recommended local sushi restaurant in Naples Florida that is happy to provide vegetarian options and they have these great little sushi tacos that you can request with vegetables only. And don’t forget to leave it up to the chef if possible. I seem to remember that once we had them with fava beans, called “Soramame” in Japanese. Crazy cool and so good!