Prepare the sauce by whisking the oyster sauce, dark soy sauce, sugar, sesame oil, and salt in a small bowl until smooth.
Heat a wok or large skillet over medium-high heat with a splash of oil and cook the beef bacon until it begins to crisp, then remove it from the pan and set aside.
Add the bell pepper, carrot, and onion to the same pan and stir-fry until they are tender yet still have a slight crunch, then remove and set aside with the bacon.
Prepare the instant noodles according to the package directions, drain them thoroughly, and add them to the hot wok with a little extra oil.
Stir the noodles constantly until they begin to brown slightly, then pour in the yakisoba sauce and toss to coat.
Return the cooked bacon and vegetables to the pan, tossing everything together until the mixture is heated through.
Spoon the noodle mixture into the hot dog buns and top with a drizzle of extra sauce, pickled ginger, and a sprinkle of seaweed if desired.