I had a very tasty meal last week at Tequila Museo Mayahuel. This restaurant, which is located about a block north of the State Capitol, has a separate vegetarian menu that specifies which dishes are vegan or can be made vegan, but you'll need to ask for it.
I tried to order the vegan Azteca Lentils Soup, which is described on the menu as a vegetarian combination of lentils, pineapple, and bananas, but the server came back from the kitchen with the news that it had been made with chicken broth. So I had some kind of potato soup in a tomato-based broth instead. It was good, but I hope they'll have a vegan version of the lentil soup available the next time I visit the restaurant.
For my entrée, I had the Enchiladas Yashu de Zapoteca, which consisted of guacamole rolled in three corn tortillas and topped with sautéed chayote, green beans, and bell peppers. I really liked the guacamole as a filling for the enchiladas. The menu has this item listed as having a vegan option available, but there doesn't appear to be anything that's not vegan in the list of ingredients. Still, it's best to make sure your server knows that you want the vegan option for whatever you order.
All of the salads on the vegetarian menu are either vegan or a vegan option is available. In addition to the enchiladas I ordered, there are two other entrées that have a vegan option available: the Chile Relleno Maya's, a roasted and stuffed poblano pepper, and the Calabacitas Mexicanas con Nopal, a dish made with zucchini and Nopal cactus in a red sauce. There are also a couple of vegan desserts: a fruit plate and sautéed plantains.
Tequila Museo Mayahuel is located at 1200 K Street. Their phone number is 916-441-7200, and their website address is http://tequilamuseo.com/. According to their Facebook page (https://www.facebook.com/MayahuelSacramento#!/MayahuelSacramento/info), they are open Monday through Wednesday from 11:00 a.m. to 10:00 p.m., Thursday and Friday from 11:00 a.m. to 12:00 a.m., and Saturday from 5:00 p.m. to 12:00 a.m. The restaurant is closed on Sunday.