This question might seem strange as almost all aircraft have the air flowing over the wing in only one direction. However if you wanted to design an airfoil would have a good L/D in the forward flow direction, but would also generate lift, or at least not have excessive drag under reverse flow conditions, how would you go a about finding such an airfoil?
The Aerobie flying disc uses an airfoil that looks like a fish. The fish tail creates stability in a spinning disc, but also quite a bit of drag I believe. If stability is not a concern, I think another airfoil shape may provide less drag.