It all depends on what and how you ask questions (and post answers). Generally you should be polite, respectful and neutral in your posts anyway, and I can hardly see a problem in your boss seeing posts like How can we keep a shared common area (kitchen) clean? unless you phrase it something like "My coworkers are a bunch of infantile incompetent slobs, how can I get back at them?". Post here almost like you're talking to an interviewer; don't throw blame around, if there was a problem explain the problem and what you want to do to overcome it.
If you're unable to ask a question in a way that appears neutral (say a question that seems to imply you're going to quit/looking at opportunities outside your current workplace), you can log out and post a question (sort of) anonymously. Just log out (click the dropdown arrow near your username at the top of the page) and post a question. The question will be attributed to "user325534" or whatever, a new unregistered account. You might have to put in a new email address but that's not publicly facing. The emails aren't validated either.
If you post a question in this way please try to keep up with comments/edits on the anonymous question like you would any other post; don't just throw a post on us and disappear. Additionally an existing post can be dissociated from your account if you ask (flag the post for moderator attention). It will show up as "anonymous" or something and won't be in your profile (and you lose the points/overall ownership). Don't make a habit of this though, only use it if you've already posted something you don't want on your "record" so to speak, since it's a bit of extra work for moderators (and Stack Exchange employees).
Personally I just used a different name when starting my Workplace account so it doesn't show up in my personal Google results. I've considered doing the same on Gaming, not really because I'm ashamed of it, but I'd really rather my User Experience and Cognitive Sciences contributions show up before anything else.