I had never heard of this minhag before but i find it interesting
from dailyhalachah.com
"The second day of Pesach, or the 16th of Nissan, is the day on which Haman was killed during the Purim story. It is therefore proper to make some commemoration of this event during one's meal on this day, a practice often referred to as "Se'udat Ester." At this meal one should speak words of Torah relevant to Ester and the Purim story, to commemorate the Jews' miraculous salvation that took place on the 16th of Nissan."
"The second day of Pesach, or the 16th of Nissan, is the day on which Haman was killed during the Purim story. It is therefore proper to make some commemoration of this event during one's meal on this day, a practice often referred to as "Se'udat Ester." At this meal one should speak words of Torah relevant to Ester and the Purim story, to commemorate the Jews' miraculous salvation that took place on the 16th of Nissan."