What's the difference between "tickets" and "pieces"?

A ticket refers to an actual record (or receipt) of a piece that can be printed out, while a Piece is a unit of production within a piecework (or hourly + piecework) job.

FieldClock can easily accommodate the printing of receipts by pairing a Bluetooth printer to print receipts.

Note 

by default, when a printer is attached it will print 1 ticket for each piece that is produced.  But there may be situations like cherry harvest where printing so many receipts is impractical. In such a situation, you can edit the configuration of your piecework within the job in question, as is detailed in "Setting or changing quantity for piecework".