In a bowl, combine napa cabbage, red chili flakes, garlic, sesame oil, rice vinegar, and salt. Stir until evenly coated, then let sit for 15 minutes so the cabbage softens and releases moisture.

In a bowl, mix soy sauce, gochujang, honey, sesame oil, garlic, ginger, and rice vinegar until smooth. Heat a large skillet or wok over high heat, then add chicken pieces and cook for 8-10 minutes until mostly cooked.

Pour in the gochujang mixture and cook for 3-4 minutes more, stirring, until caramelized and chicken is cooked through. The sauce should look glossy and cling to the pieces.

Warm flour tortillas in a dry skillet over medium heat for 30-60 seconds per side until pliable and lightly toasted. Fill each tortilla with Korean BBQ chicken, top with quick kimchi, and garnish with sliced scallions and sesame seeds.

Serve immediately while the chicken glaze is sticky and the tortillas are warm. Add a final sprinkle of sesame seeds if desired and keep toppings from sliding by piling kimchi lightly.