The best way is to use Process Lasso’s rules to create sticky CPU affinities that persist.
Alternatively, if you want to start a program at a specific CPU affinity once, you can use cmd.exe’s Start command:
start /affinity 0x0000000000055500 notepad.exe
When run from the Start Menu, you would need to include the command shell (cmd.exe), for example:
c:\windows\system32\cmd.exe /C start /affinity 0x0000000000055500 notepad.exe