We present full-wave electromagnetic optimization of corrugated metallic sheets to achieve maximum power focusing at desired locations when illuminated by plane waves. The corrugations are freely applied by moving the discretization nodes, leading to huge optimization spaces that are scanned by employing genetic algorithms. The required simulations are performed accurately and efficiently via the method of moments or the multilevel fast multipole algorithm. Hundreds of thousands of simulations are performed to demonstrate the feasibility of strong optical focusing, even with relatively small sheets in terms of wavelength. The corrugated sheets can be useful in various applications, such as energy harvesting, solar cells, imaging, and optical sensing.