As kbin is so new, there is no equivalent to RES (Reddit Enhancement Suite) yet. However there is an easy way to switch user accounts - at least for those of you using Firefox.

One of the official Mozilla extensions for Firefox is this:

Firefox Multi-Account Containers
https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers/

Essentially, this lets you create and use multiple browser "containers", where each container has its own set of cookies completely segregated from the others.

That means you can create one container where you are logged into kbin under your regular account, another container where you are logged into your NSFW account, another container where you are logged in under your moderator account, etc...

It's also very helpful for any other sites where you have multiple accounts and want a convenient way to switch between them (i.e. Google Mail, etc...).

You can easily switch between containers - which takes effect ONLY on that browser window, not universally. That means you can be logged into kbin, Gmail, or any place else - simultaneously under multiple accounts (i.e. one browser window has gmail logged in under your personal account, while another browser window has gmail logged in under your work account).