01 - Pound chicken thighs to uniform 1/4-inch thickness. Season both sides generously with salt and pepper.
02 - Dredge each thigh in flour, shaking off excess. Dip into beaten egg whisked with milk, then press firmly into panko crumbs to coat completely.
03 - Heat 1/2 inch vegetable oil in skillet over medium heat until shimmering. Fry chicken 3-4 minutes per side until deep golden brown and internal temperature reaches 165°F. Drain on paper towels and slice into musubi-width strips.
04 - Whisk rice vinegar, sugar, and salt until dissolved. Gently fold mixture into warm rice, taking care not to mash grains. Allow to cool until manageable to handle.
05 - Combine tonkatsu sauce, soy sauce, and honey in small bowl. Whisk until smooth and fully integrated.
06 - Lay halved nori sheet shiny side down on plastic wrap. With moistened hands, press 1/4 cup seasoned rice into compact rectangle, approximately 3 by 2 inches, centered on nori.
07 - Sprinkle rice with furikake if desired. Place chicken katsu slice over rice. Drizzle lightly with prepared sauce. Top with thin layer of rice, pressing gently to adhere.
08 - Fold nori tightly around filling using plastic wrap as guide. Compress firmly to shape. Rest 2-3 minutes allowing nori to soften and seal. Remove plastic wrap before serving.