That is a something I didn't think about, how do you hang anything with block walls. Drill a hole and put a screw in ?
Most houses (including mine) here are brick and concrete on top. Actually, it is not "concrete" but usually something not as hard:
which I can't find a correct English name for: plaster!
In any case, you can still hammer nails in it, and, in some occasions, when concrete is particularly hard, yes, that's exactly what you do: drill a hole and place a concrete fastener in. standard practice here (Italy). Wooden walls are extremely rare.