Mix the sliced green cabbage, red cabbage, kkaetnip (if using), carrot, red chili (if using), Serrano or jalapeno, and garlic in a large bowl.
In a small bowl, mix the gochujang, gochugaru (if using), rice vinegar, soy sauce, and agave nectar or sugar. Add the sesame seeds and stir to combine.
Pour the sauce over the vegetable mixture and toss to coat evenly.
Serve the bibim mandu by placing the crispy dumplings on a plate and topping with the bibim vegetable mixture.
