Tips: Arepa flour is precooked cornmeal. It is not the same as regular cornmeal or masa harina (the cornmeal used to make tortillas), neither of which will work to make arepas. You can find arepa flour in the international section of most supermarkets--the two most popular brands are P.A.N. and Goya.
Moistening your hands with a bit of water helps prevent the dough from sticking to them. If the outer edges of the arepas crack when pressed, your dough is too dry; moisten your hands with water, shape the dough back into a ball and press again. If the dough won't hold its shape, it is too wet; add arepa flour 1 Tbsp. at a time and mix again.
To make ahead: Cook chicken (Step 2), cover and refrigerate for up to 2 days.