Mix cornmeal with salt and cheese. Heat milk in a saucepan over medium low heat until steam rises. Add butter and stir until melted.
Remove milk from heat and stir into cornmeal mixture until a thick batter forms. Fold in corn kernels, green onion, cilantro and jalapeño.
Let batter rest until it thickens into a soft dough, about 15 minutes. Gently form 3- to 4-inch balls from the batter and flatten in the palm of your hand. They should be about 1/2-inch thick. Refrigerate for a while until they firm up.
Heat oil inn a large skillet and shallow fry areas, working batches until golden brown on each side, about 5 minutes for the first side and 3 minutes for the second. When all areas are cooked and cool enough to handle, choose your style to serve: Venezuelans, cut a pocket and stuff the areas with beans, vegetables and top with sour cream; Colombians make a larger and flatter arepa and top with beans, vegetables, cheese and sour cream (pizza style).