How can I eliminate unneeded receptacles?
Yes, if you have your heart set on removing them, then after you remove the outlet, tie the two black wires together with a wirenut, and tie the two white wires together.  That way, you will still have power going to wherever the next electrical box is.

For the ground, you can either screw it to the box, if it is a metal box and you can find a place to do that, or just leave it unconnected in the box.  If you have two ground wires (one entering the box and one leaving), tie these two ground wires together.

Don't forget: before you remove the faceplate and start removing wires, disconnect the circuit by turning off the appropriate circuit breaker, and then test to make sure that the outlet is dead.