Running a USB key on Ubuntu system

I have a USB key with a startup utility manager (PStart), and several programs for maintenance and productivity. Problem is, it is Windows configured, so when I am at friends' places with a Linux box or MacOS, I can't use any of them. Major problem is that I cannot even see the trash folder and permanently delete files to make more space.

1. Is there a way to use this drive apps on these machines?
2. Or where can I set up on it portable apps that do a comparable job on non-Windows machines?
3. At the very least, how can I permanently remove files while on these machines, so I can clear space for large file transfer, if I have accidentally not permanently deleted unneeded files?

Thanks in advance.