Peppermint OS' Ice SSB (site specific browser) is probably the sleekest "app mode" web browser launcher creator we've seen. Now, you can create a native-looking app for any web site, complete with profile independence, and the ability to use Chrome, Chromium, Vivaldi or Firefox as the back-end. We'll install it and test on Linux Mint, but it should work on any Debian-based Linux distro (such as Ubuntu), or others if you don't mind compiling it yourself.