This is just a guess, but the first place I’d look would be what
command-line arguments Acrobat Reader supports under Linux. There’s a
good chance you can pass the name of an xfdf to acrobat this way, so you
could just use %x{ } to launch it with the appropriate form data.
If you need more automation than that (for example, to automatically
print the resulting form), I know Acrobat is highly scriptable using
Javascript. If it supports being passed a Javascript file on the command
line, you could generate the xfdf file, then generate a short javascript
file that tells Acrobat to open up and print the form.