Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
The king now learned, perhaps for the first time, that his favorite was a Jewess.
Although the enemy ... - i. e. "although the enemy (Haman) would not (even in that case) compensate (by his payment to the treasury) for the king's loss of so many subjects."
Like the Greeks and Romans, the Persians reclined at their meals on sofas or couches. Haman, in the intensity of his supplication, had thrown himself upon the couch at Esther's feet.
They covered Haman's face - The Macedonians and the Romans are known to have commonly muffled the heads of prisoners before executing them. It may have also been a Persian custom.