01 - Pound chicken thighs to even thickness. Season both sides generously with salt and pepper.
02 - Dredge each thigh in flour, dip in beaten egg mixed with milk, then coat thoroughly with panko breadcrumbs.
03 - Heat about 1/2 inch vegetable oil in skillet over medium heat. Fry chicken until golden and cooked through, 3-4 minutes per side. Drain on paper towels and slice into strips to fit musubi.
04 - Mix rice vinegar, sugar, and salt in small bowl. Gently fold into warm rice. Let cool slightly.
05 - Whisk together tonkatsu sauce, soy sauce, and honey until combined.
06 - Place plastic wrap on flat surface. Lay halved nori shiny side down. With wet hands, press 1/4 cup rice into compact rectangle on nori center. Sprinkle with furikake if desired.
07 - Top with chicken katsu slice and drizzle with sauce. Add thin rice layer, pressing gently. Wrap nori tightly around filling using plastic wrap to compress. Let sit 2-3 minutes for nori to soften. Remove plastic and repeat.