What are vegetarian "sushi" rolls called?!
Answers: they have a cream cheese base and contain no actual fish.
"Maki" refers to roll, albeit any roll. But Kappa maki are specifically Japanese cucumber roll.
In regards to your question, usually veg rolls are unique to the specific Japanese restaurant you visit. The names may differ from restaurant to restaurant and they are usually "in house" creations.
There are lots of varieties of veg rolls: cream cheese cucumber rolls, some contain avocado. I have had veg tempura rolls, carrot and cucumber rolls, bell pepper rolls, shiitake rolls....basically any vegetable can be made into a sushi roll by a creative sushi chef.
I think you are referring to "maki".
California rolls
There is no special name in Japanese for vegetarian sushi rolls. The word 'maki' means 'roll' in Japanese.
There are several maki with cream cheese available in America, but they are a Western invention. Often, rolls with cream cheese and smoked salmon or cream cheese and asparagus are popular. But because they are a recent Western invention, there are no 'standards' or well-known, universal rolls with Japanese names that you can refer to.