Flattening chicken breast halves serves two purposes: It provides more surface area to rub in the Greek-influenced seasoning, and it ensures that the chicken cooks quickly.
(transitive,idiomatic) To irritatingly make a point.
2003 March 9,Glenn Davis,“U.S. vs. Mexico a day of celebration, opportunity”, inHouston Chronicle:
Postcards from Florida might mean someone is rubbing in the fact he or she has been lounging on the white, sandy beaches