How can I hang something on an exterior wall with vinyl siding?
The siding needs to remain free to expand and contract.  So cutting at least a slot , then hanging something through that would work, but would be unsightly, and would leak water through the hole.  So I think that finding some kind of gasket or trim piece (such as is found where your vents protrude through siding) and trimming with J-channel all around it would look better and would be less prone to leaks.