If you only need to use an app and not the rest of the environment you can also run it as a Chrome plugin under ARC and not mess with virtualization at all.
Edit: instructions.
I downloaded Genymotion from https://www.genymotion.com/pricing-and-licensing/ (Individual, Basic, which costs no money). It's enough to run Android but you don't have Google Play.
I followed these general directions to install it https://inthecheesefactory.com/blog/how-to-install-google-se...
However the filetrip link didn't work (and I don't know if I want to trust it) and the google apps failed to install. I googled and eventually downloaded these files:
ARM to x86 translation: http://forum.xda-developers.com/android/general/guide-genymo...
Google Play: https://www.androidfilehost.com/?fid=24591023225177410 (banks_dynamic_gapps)
The latter is for Android 6 so you should run an Android 6 image on your emulated device.
My computer is still fine after installing those two files in the Android emulator but I don't take responsibility. Don't know how verified they are.
Is there a way to run Android apps in a VM on Linux?
A VM for phone applications would be similar to a browser. A browser runs websites in a safe environment. A way to run apps in a safe environment would be nice.