What is the ruling on placing the hands on the face after concluding the prayer (taslim), and placing the hand on the chest after greeting a Muslim brother with salaam? Is this considered an innovation (bid'ah) or impermissible (haram)? And how can one object to these practices, providing evidence from the Qur'an and Sunnah?

Wiping the face with the hands after finishing prayer or supplication is not legislated, as it has not been reported in the Sunnah (definition) of the Prophet, peace and blessings be upon him. As for shaking hands, it is recommended and among the reasons for the forgiveness of sins. If a person places his hand on his chest after shaking hands as a form of respect or greeting, there is no harm in it, provided that it is not attributed to the Prophet's Sunnah and is considered a custom rather than a Sunnah.