I am removing a switch from a gang box. What is the appropriate way to cap the circuit?
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.