From which sea did Hashem blow the quails?
Seforno: He blew them from the Yam-Suf, which was due south of where they were encamped. 1
What is the significance of the fact that the quails lay in piles of a height of two Amos?
Rashi: This was the level of a person's heart - to enable them to collect them with ease, without having to reach for it or to bend down. Refer to 11:23:2:4.
Why did Hashem send specifically Slav?
Moshav Zekenim: Moshe discussed animals, which were created from the dry land, and fish, which were created from the water. I will give to them something from a different source