South exit from Koenji station,
Turn left,
Keep going past McDonalds and the Mizuho Bank ATM,
You will come to Central Road.
At the top, it's a bit seedy, with what could be described as Koenji's red light area, or one of them anyway: http://koenji-live.blogspot.com/2009/01/gentlemans-relaxation-zone.html
Once past that, you got some small bars, restaurants, Japan's only Tesco's(!), junk shops, and some of the best decorated shop fronts in Tokyo.
This is just two of them:
Nincompoop Capacity and Garter.
Someone's let their creative juices flow with these.