There are a couple of vegan options and are labelled as such. The Berkeley, Austin and New Delhi are great. They sell a few other flavors frozen only. The New Delhi is quite tasty and ingenious blend of flavors, coconut milk, sweet potato.
The restaurant is decidedly un-fancy, order at counter, food in baskets. You can also get the tamales hot or frozen at the farmer's market, such as Sundays at the St. Philips Plaza. You can also find them frozen at Sunflower and Whole Foods.
The tamales are pretty good, but overpriced for what you get. $6-7 for 2 tamales. Eh.