I had lunch at Chipotle Mexican Grill in West Sacramento with my son Zack over the weekend. While the vegan options there are somewhat limited, it's still very easy to be a vegan at Chipotle.
I had a rice and bean burrito made with black beans, Chipotle's new brown rice option, and salsa. Other items that I could have had on my burrito were the cilantro-lime white rice, sautéed vegetables (onion and bell pepper), and guacamole. It's also possible to order a burrito bowl, which would include the same ingredients but would be served over a bed of lettuce instead of wrapped in a tortilla.
Here's the information for vegans that appears on the Chipotle website: "Vegan Options. You should avoid our pinto beans (they are cooked with a small amount of bacon), meats (obviously), cheese, sour cream, and chipotle-honey vinaigrette."
In addition to the nutritional information that appears on the restaurant's website, Chipotle also has a "Food with Integrity" section that discusses their efforts to use local organic produce grown on family farms to the extent possible. For example, forty percent of the beans they use are organically grown, and they actively seek out local produce suppliers.
Chipotle Mexican Grill is a national chain with several locations in the Sacramento area. More information about their locations or their menu is available at http://www.chipotle.com/en-US/Default.aspx?type=default.