Prep the salmon: Pat the salmon cubes dry with paper towels. Dry fish browns better and gets crisp.
Season lightly with salt and pepper.
Coat for crispiness: Toss salmon with cornstarch until each piece has a thin, even coating. Shake off excess. You want a dusting, not clumps.
Make the glaze: In a small bowl, whisk honey, soy or tamari, minced garlic, rice vinegar or lime juice, and red pepper flakes or sriracha.
Stir in sesame oil if using. Set aside.
Heat the pan: Place a large nonstick or stainless skillet over medium-high heat. Add 1–2 tablespoons oil and let it get hot until shimmering.
Sear the salmon: Add salmon in a single layer without crowding.
Cook 2–3 minutes on the first side until golden and crisp. Flip and cook 1–2 minutes more. Work in batches if needed.
Transfer to a plate.
Deglaze and glaze: Reduce heat to medium. Add the honey garlic mixture to the pan. Let it bubble for 30–60 seconds until slightly thickened.
Finish with butter: Stir in butter (optional) for a silky, glossy sauce.
Return salmon to the pan and toss gently until coated. Cook 30–60 seconds more to set the glaze. Don’t overdo it—salmon cooks fast.
Garnish and serve: Sprinkle with green onions and sesame seeds.
Serve immediately with rice, cucumbers, or in lettuce cups with a squeeze of lime.