Mix all the pepper-salt blend ingredients (salt, pepper, umami seasoning, garlic powder) in a small dish, breaking up any lumps.
Combine the sauce (tare) ingredients (soy sauce, mirin, sugar, umami seasoning) in a small pan and warm over medium heat until the sugar dissolves; turn off the heat once it bubbles.
Heat oil in a frying pan — a shallow pool halfway up the wings to save oil (turn often), or a full pot for proper deep-frying. Fry the wings, turning, until deep golden and genuinely crisp all over.
Drain the wings. While hot, brush the sauce (tare) all over each wing, then sprinkle over the pepper-salt blend from step 1 (and sesame seeds if you like). Serve immediately.