And what do you mean by "Linux"? Would GNU coreutils and a terminal be sufficient, or is there something else you need?
These links might be useful:
https://sturmflut.github.io/ubuntu/bq/2015/07/02/hacking-the...
https://github.com/bq/aquaris-E4.5/tree/aquaris-E4.5-ubuntu-...
I would seriously avoid using the browser, especially with Flash on that device at this point. Also I believe there's only a DoS CVE for SSH.
With the OTG USB, they're still a cheaper alternative to lots of Raspberry Pi projects.
Android used to use it own process-based virtual machine; Dalvik. This is not the case anymore. Now Android Runtime (ART) is used. Applications are compiled to native machine code upon installation. There is no virtual machine.
What about apps created with the NDK?