Blanch the tofu noodles and rice noodles in boiling water, then drain in a strainer.
Cut the beef brisket slices into bite-sized pieces.
Stir-fry the beef brisket in a pan; when the fat is rendered, add kimchi and stir-fry together.
When the kimchi is well-cooked, add the tofu noodles and rice noodles, then stir-fry everything together.
Season to taste with salt and pepper.
Place the finished stir-fry in a serving dish.