What are my options if I find out a car dealership sold me a "New" car that had previouly had been in accident?

If it is a 2014 model, then you could not have thought it was new in 2015.  However, if the odometer said zero, then that is a crime.  Call the DA in your county.  Ask for the consumer fraud division.  Given it is a year later, it is hard to prove that value was reduced by collision in 2014, and not your usage.  Thus, a civil remedy is less likely.