Several concepts of coherent control are extended to manipulate light propagating along metal nano-particle arrays. A phase-polarization control strategy is proposed and applied to control the electromagnetic energy transport via nano-array constructs with multiple branching intersections, leading to an optical switch or inverter far below the diffraction limit. An optimal control approach, based on the genetic algorithm optimization procedure, is next generalized to suggest a systematic design tool for plasmonic nano-devices, where both material properties of nano-arrays and incident field parameters are optimized in order to make devices with desired functionality. The proposed schemes are also used to better understand the physics underlying the phenomenon of electromagnetic energy transport via metal nano-constructs. Several applications of the phase-polarization and optimal control strategies are considered.