Margaret M. Ciechanowski, M.D., of Glen Ridge, N.J., and George J. Ciechanowski, M.D., of Lake Hopatcong, N.J., have announced the engagement of their daughter Tesia Eva Ciechanowski to Timothy Joseph Henn, a son of Marie T. Gallagher and Joseph G. Henn of Darien, Conn., and East Hampton.