There are a number of ways.
Define a calculation field that returns text as:
Right ( BarcodeScanField ; Length ( BarcodeScanField ) - 1 )
That keeps the raw scan in one field and the scan minus first character in another.
You can also use:
Right ( self ; Length ( self ) - 1 )
As an auto-enter by calculation expression on the field that receives the scanned text, clear the "do not replace existing value..." option and any text entered into the field will automatically have the leftmost character removed so your scan can have the first character discarded at the moment it's scanned if you want.
Thank you !