Make the chili: In a large saucepan over medium-low heat, stir together the barbecue sauce, kidney beans, black beans, chili seasoning, brown sugar and mustard. Bring to a boil, then reduce the heat and simmer for 10 to 12 minutes, stirring occasionally.
Meanwhile, make the hot dogs: Set up a grill or preheat a grill pan over medium heat. When ready to start cooking, brush the grates with vegetable oil.
Place the hot dogs on the hot oiled grill and cook, turning occasionally, for 10 minutes or until heated through. Toast the buns on the grill, if desired.
Put the hot dogs in the buns and top with the chili.
