The adsorption of R-phenylglycine on Cu(110) surfaces shows that the periodic superstructure of the chiral overlayer destroys the substrate mirror plane symmetry. Here, we report on the novel linear dichroism electron scattering method to determine the chirality, based on the unique symmetry of the chiral surface. The details of the molecular structure, with the absolute surface chirality, are derived from the azimuthal variation of intensity of individual vibrational modes.