Wash your hands
In a medium bowl add water and salt. Mix until the salt is dissolved.
Slowly add the harina P.A.N. Mix with your hands, making circular movements and breaking with your finger the lumps that may form. Let rest 5 minutes to let the mixture thicken.
Preheat a non-stick 11 inch square griddle over medium heat. If you don't have a griddle you can use a skillet instead.
After 5 minutes add the oil and work it in with your hands for 2 minutes. The dough should be firm enough holds its shape without cracking when molded. If it is too soft add a little more of harina P.A.N; if too hard add a little more water.
Form balls and flatten them gently until they're about 1/2-inch thick discs.
Place the discs over the preheat griddle and cook the arepas for 5-7 minutes on each side or until lightly golden brown.
Split each arepa in half and fill with and fill them with whatever you like: cheese, ham, egg, beans, chicken, beef, tuna ... your creativity is the limit.