No, with the select tool you can only select entities. Entities are persistent objects that have properties, attributes, are selectable and are stored in the .skp file. Something drawn on the viewport just has the appearance of an entity, but does not exist longer than a frame (then it needs to be redrawn for the next frame).
You can create almost anything with the SketchUp API. You can of course create an extension that, when it is active, simulates the native select tool but highlights things that are no real entities. But these can only be selected with your extension.
But why not create a real face and assign a transparent blue material to it?