Not sure about on a hypervisor, but if you're using Docker, you could do something like:
FROM scratch
COPY ./bin/app /app
ENTRYPOINT ["app"]
which will make a barebones image with no OS cruft. You need to make sure your binary _is_ truly statically linked though. The key being the inclusion of musl libc in in the OP's build.
I've tried this with golang and you need to pass some odd flags I can't remember off the top of my head to get it to not dynamically link gnu libc, but once working you have container images that are incredibly small.
I'd imagine with a minimal container host like CoreOS you get largely the same effect as running Erlang on Xen.
Quite hard. I don't think any of the rust unikernel projects really have gotten off ground to even serve "hello world" web requests, and there has been several attempts.
