How to Make It
Preheat the oven to 350°. In a large bowl, mix the arepa meal with the salt and sugar. Stir in the warm water. Press out any lumps in the dough. Cover the bowl and let the dough stand for 10 minutes, until firm.
Using moistened hands, divide the dough into 4 pieces. Roll each piece into a 12-inch rope. Cut each rope into 9 pieces and keep covered with a damp towel. Using moistened hands, roll each piece into a ball and flatten into a 2 1/2-inch round, a scant 1/2 inch thick. Keep covered.
Heat 1/4 cup of vegetable oil in each of 2 large nonstick skillets. Working in batches, fry the arepas over moderate heat, turning occasionally, until golden and crisp, about 7 minutes. Add more oil to the skillet as necessary. Drain the arepas on paper towels and transfer to a large baking sheet.
Using a small serrated knife, split each arepa horizontally. Fill them with the cheese and ham and return to the baking sheet. Bake for about 5 minutes, until the cheese is melted. Transfer the arepas to a platter and serve warm, with hot sauce.
When buying arepa meal, look for brands such as P.A.N. or Goya at supermarkets.