A new formalism designed to treat long range interactions on surfaces, systems which are infinitely replicated in two spatial directions but have finite extent in the third, is developed. The new formalism is based in reciprocal space and, thus, permits the facile extension of standard plane-wave based density functional theory, Ewald summation, and smooth particle-mesh Ewald methods to handle surfaces efficiently. The method is tested on both model (body centered cubic lattices) and realistic problems (an ice surface with a defect and the 2x1 surface reconstruction of silicon) and found to be accurate, efficient, and a marked improvement on existing formulations in speed, accuracy, and utility.