In the recent graphic novel Vader (I don't know which one), when Darth Vader gets his suit shut down, how was he able to turn everything back on, and then kill that officer? Am I missing something? Has this been addressed in that graphic novel?
Vader used the Force to control the kill switch and reactivated his cybernetic suit.
Darth Vader: Nothing is impossible for the Force.
You're most likely referring to Darth Vader: End of Games series by Marvel Comics. In the 23rd issue, Imperial scientist officer Cylo, who also participated in constructing Vader's suit, uses his secret kill switch to disable the cybernetics, as the dark lord was coming to kill him. He had prepared and kept the device "just in case".
Continued in the 24th issue, while unable to operate, Vader made a mental trip to his history and grew greater in his anger. Raged by the memories of the past, he was able to call for the Dark Side of the Force, and telekinetically control the kill switch button. This activated Vader's armor again and he stabbed Cylo with his lightsaber.
I can't speak as to the specific circumstances since I haven't seen the novel, but you seem to be forgetting who Darth Vader used to be.
Anakin Skywalker has proven to be a genius engineer. As a kid, he built both C3PO and his own pod racer. When the thing wouldn't start, he very quickly fixed it. (Edit: this happened twice. Once before the race started when JarJar's tongue got paralyzed, and another time when the race started)
So you can assume Anakin's engineering skill to be exceptional. Anakin's genius is continually referenced in The Phantom Menace.
Not only is he a master engineer, but he has also been confined to a machine (the suit) that he needs to stay alive. It seems most likely that he has tinkered with it for as long as he's had the suit. Even if he hasn't made any changes to it, he will at least know how the suit works, down to every intricate little detail (if he can build a functional pod racer from scraps...)
If anyone could manage to restart the suit abnormally quickly; my money is on the genius engineer who has been using the suit for the better part of his life.
It's a working theory (afaik) that Anakin channeled the Force when he tinkered with machines as a child. That may be the case, but it is irrelevant for this answer.
Whatever compelled him to be an excellent engineer as a child (whether skill, talent or force wielding aptitude), he uses the same when rebooting his own suit.