Create a macro in the database that opens the form and navigates to the record or that calls a VBA procedure that does that. You can call the macro with the Ms Access /x switch. If you need to pass the record number, you can pass it with the /cmd switch. See:
http://support.microsoft.com/kb/209207 Sample Access command line with switches (for A2003 - each version of Access is in a different folder):
C:\Program Files\Microsoft Office\OFFICE11\MSACCESS.E
XE C:SomeFolder/MyDatabase.md
b /x "OpenFormMacro" /cmd "123"