Pat each hot dog dry with a paper towel. Push a wooden skewer or posicle stick into each hot dog. Lightly sprinkle the hot dogs with cornstarch. Using your fingers, rub the cornstarch evenly over the hot dogs to form a very light coating. Set aside.
In a large bowl, add the dry ingredients and give a stir to combine. Once full combined, mix in the milk, egg, and jalapeno. Stir until the batter is smooth and without lumps. You may need to add 1-2 tablespoons of flour; the batter should be thick enough to cling to the hot dog. Pour the batter into a tall glass for easier dipping.
Heat the oil in a large pot until it reaches 350F.
Holding the tip of the skewer, take a hot dog and dip it fully into the batter, lifting it out, then rotating it to let excess batter drip off. Using tongs, carefully place the battered dog into the hot oil. Hold it fully submerged for 30-60 seconds until a crust forms, then rotate it so that it fries evenly. Cook for 3-5 minutes , or until golden brown. Repeat with the remaing hot dogs. Serve with mustard for dipping. If you are thinking about using ketchup instead, please get off my website and never come back.