1)
What is "Ru'ach Kadim"?
1.
Rashi: It is an expression of payment (punishment) that Hashem takes from Resha'im - "va'Yolech Hashem Es ha'Yam b'Ru'ach Kadim" (Shemos 14:21), and in Tzor, "Ru'ach ha'Kadim Shevarech b'Lev Yam" (Yechezkel 27:26).
2.
Radak, Malbim: [It is as if they were stricken via] a strong east wind.
2)
Where is "Tarshish"?
1.
Rashi: It is the neighbor of Tzor. It is Africa; it is from Edom.
2.
Radak: It is a harbor for boats - "va'Yimtza Aniyah Ba'ah Tarshish" (Yonah 1:3).
