This paper presents methods for optimizing application-specific networks-on-chips (NoCs). We show that wave pipelining provides more energy efficient data transport than non-wave pipelined communication. We observe 52% energy saving, 60% transistor area saving, and 1.7 times speedup by using wave pipelining in simulation. Wave pipelining is particularly well suited to networks-on-chips because the networkes structured interconnection provides better delay control. Our analysis shows how designers can tune their network to the requirements of the application by choosing a design point along area/performance or area/energy curves.