Recent developments in nanofabrication and optical near-field metrology have faced complementary modeling techniques with new demands. We present a surface integral formulation that accurately describes the extreme near-field of a plasmonic nanoparticle in addition to its far-field properties. Flexible surface meshing gives precise control over even complex geometries allowing investigation of the effects of fabrication accuracy and material homogeneity on a particle's optical response. Using this technique, the influence of a particle's symmetry and shape on surrounding "hot spots" of extremely large field enhancement is explored, giving insight into the mechanisms of surface enhanced Raman scattering and single-molecule detection techniques.