How do you get Akimbo perk?

I don't know where you heard that akimbo is a perk but it isn't. Akimbo is only for certain guns ( like all handguns, machine pistols, and some shotguns.) It is a weapon attachment that you need to get a certain amount of kills to get like for Handguns it is 50, Shotguns 10. So if you want akimbo just get kills with the weapon you want it with.