If your problem is while using the editor ...you might find it easier to select objects from the Project bar list instead unless of course the object you are picking is an Instance of another object ..if so well...within the editor all you can do is remember the coordinates and then move the top object to get the under object...
unless of course the under object is located on its own layer..if thats the case just disable the top layer ...
There is a request thread in the general section to ask to address that situation....if its in game you are talking about...Try shinkan's Event:)