In response to Josh Grajower's request for background reading suggestions for teaching Amalek and Genocide, I would recommend Avi Sagi, "The Punishment of Amalek in Jewish Tradition: Coping With the Moral Problem," Harvard Theological Review, 87:3 (1994) pp. 323-346. Also the chapter on Amalek in Elliot Horowitz, Reckless Rites: Purim and the Legacy of Jewish Violence, Princeton U. Press, 2008. For a discussion of rabbinic efforts to reframe the episodes in Sefer Shmuel in which Shaul spares Amalek and slaughters the priests of Nov, see my recently published (Hebrew) article, "King Saul's Nemesis: Compassion or Cruelty," in Ushmu'el Beqore'e Shemo, the Shmuel Leiter Memorial Volume (or write me to request PDF).
Baruch Feldstern