In a mixing bowl, whisk together soy sauce, sesame oil, lime juice, garlic powder, ground ginger, and optional chili flakes until well combined. Place the boneless skinless chicken thighs in the marinade and let marinate for at least 20 minutes.

Combine creamy peanut butter, soy sauce, honey, rice vinegar, sesame oil, and minced garlic in a separate bowl. Mix until smooth, then gradually add warm water to achieve a pourable consistency.

In a large bowl, combine shredded cabbage, julienne carrots, red bell pepper, scallions, and cilantro. Drizzle with lime juice, rice vinegar, sugar, and toss everything together. Let sit for about 10 minutes.

Heat a grill pan over medium-high heat, add marinated chicken and cook for about 5-7 minutes per side until cooked through. Let rest for 5 minutes before slicing.

Warm tortillas in a dry skillet. Spread peanut sauce, add slaw and sliced chicken, drizzle more peanut sauce, then roll tightly and cut in half to serve.