What is the easiest solution to add receptacle along an unfinished, exterior, insulated, basement wall?
I think the easiest solution is to cut the vapor barrier in the section(s) the outlets will be located in. Cut along the studs. The install outlets/wiring between stud/insulation. Then, simply cut a new vapor barrier section, tape to seal. You don't need to take the entire vapor barrier down (unless you don't trust the tape seal--which if true, I also  presume you'd want to replace the entire vapor barrier?)

You may not plan to finish the basement, but the next owner may. Having receptacles flush with the studs will make it easy--if/when that time ever comes.