I'm Ph.D. educated, worked for major US corporations (Senior Mgmt), and am sick of US laws (CA in particular) that prevent me from being hired due to my felony (DUI). Am ready to renounce my citizenship; what countries are most likely to grant me citizenship, and a new start? I'm fluent in Spanish, can teach, can work in economic analysis/international development/demand forecasting/etc. THX.

You will need to pick one, move there and request citizenship, just as aliens from other nations come here.

You will want to rule out any Europe nation since your criminal record will show up though criminal checks there also if they run it international, if you say or show you ever lived in the US. Interpol does all of the International background checks for most nations

Next you will have to pick one where your felony will not stop your citizenship. Perhaps something in South America