In my new house I have a couple rooms where the wall switch controls the outlets. I would like to remove the switch and cap the wires and then install a blank wall plate. What is the proper way to cap the wires? I have not opened the box yet but I would gather that the switch has two blacks and a ground.
If the switches are basic (not 3-way and not having some special feature needing a neutral), you are correct.
The simplest way to remove the switch and leave the outlets always live is to twist the two wires (other than the bare or green ground wire) from the switch together and cover with a wire nut. These will most likely be both black, black and red, or black and white (but the white will be hot, and if code was followed, marked with black tape, paint or marker).
The ground wire can simply be removed and pushed to the back of the box, but to avoid the risk of a bare wire touching a live wore or terminal, you may want to add a wire nut to the end of the ground as well.
You can then put a blank cover plate over the switch box.