In a medium bowl, whisk together the soy sauce, sesame oil, lime juice, garlic powder, ginger, and chili flakes. Add the chicken thighs and toss until well coated. Let them marinate for at least 20 minutes at room temperature, or cover and refrigerate for up to 4 hours.

In a small bowl, combine the peanut butter, soy sauce, honey, rice vinegar, sesame oil, minced garlic, and grated ginger. Whisk until smooth. Add warm water, one tablespoon at a time, whisking until you reach a pourable consistency. Set aside.

In a large bowl, combine the green cabbage, red cabbage, carrots, bell pepper, scallions, and cilantro. Add the lime juice, rice vinegar, sugar, and a pinch of salt. Toss well to coat. Let the slaw sit for about 10 minutes to allow the flavors to meld.

Heat a grill pan or large skillet over medium-high heat. Add a drizzle of oil. Cook the marinated chicken thighs for 5 to 7 minutes per side, until cooked through and nicely browned. Transfer to a cutting board and let rest for 5 minutes, then slice thinly against the grain.

Warm the tortillas briefly in a dry skillet or microwave until pliable. Lay each tortilla flat and spread a generous spoonful of peanut sauce across the bottom. Top with a handful of slaw, followed by the sliced chicken. Drizzle a little more peanut sauce over the chicken, and garnish with extra cilantro and chopped peanuts if desired.

Fold the bottom of the tortilla up over the filling, then fold in the sides and roll tightly like a burrito. Slice in half and serve immediately.