I do not know if this is that duaa? Allahumma tahhir qalbi minan nifaaqi wa amali minar riyaai' wa lisani minal kazibi wa aini minal khiyanati fa innaka ta'alamu khaainatal a'yuni wa maa tukhfis sudoor. "O Allah! purify my heart from hypocrisy, my actions from ostentation, my tongue from lies, my eyes from treachery for verily You know the treachery of eyes and whatever the hearts conceal."