I played a match (pvp, non-ranked) where I was beat so soundly by this Akali build that I resolved to document and learn from it. The player was Nvylion56 and the only thing he said all match was "Ghostmode Akali rapes face". This guide is my documentation. I have not yet mastered this. I have only what I observed, the replay, the players profile, and my experiments to go from.

I have not yet figured out the skill levels. I'm pretty sure that pre-ult you prioritize Q. Post ult I do not know.

Take this Akali mid. Use your Q to score last hits. Use your W to escape. You should take almost no damage. Do not dive for the kills. Do not take unnecessary risks. If you are doing well you won't have to go back until about the 8 minute mark.

Every opportunity should start with you harassing with your Q. If your Q is on the target, and the target does something dumb to create an opening you dive with R, spam E, then throw your W to cover you.

Hide in your W between cooldowns.

Use your ult to jump to minions to avoid danger.

Pick up buffs when/if you can. Jungle farm is good, but don't starve your team.

Prioritize avoiding damage. You can jump in, do some damage, and jump out fast enough to take almost no hits. Rely on your team to keep the fight going so you can repeat the process.

If you did everything right, you should end up here: Fed. At this point enemies should fear you. This is where you can take risks. This is the phase where you can ult under a turret, get a kill, then ult to a minion to avoid turret damage.