We are guilty of cooking things like boiled chicken, chop turkey/meat, potatoes, yams all boiled and no spices. We mix it in with kibble everyday. We also use high value food like turkey for reinforcing or instilling new behaviors.
As for begging at the table we teach all dogs to either sit and ask for things or lay down in their beds while we eat. We have had great success with this because we all know dogs are opportunist and do what works