Preheat the oven to 400°F (200°C). Pat the 4 frozen salmon fillets dry, heat the 2 tbsp olive oil in an oven-safe skillet over medium-high, and sear the fillets skin-side down for 4 minutes until the skin is golden and releases cleanly.

While the salmon sears, whisk together the 3 tbsp soy sauce, 2 tbsp honey, 1 tbsp rice vinegar, 3 cloves minced garlic, 1 tsp grated ginger, and 1/2 tsp red pepper flakes in a small bowl until smooth.

Flip the fillets flesh-side down for 1 minute, flip back skin-side down, pour the glaze over each fillet, and transfer the skillet to the oven. Roast for 8 to 10 minutes until the internal temperature reaches 125°F (52°C) for medium or 145°F (63°C) for fully cooked.

Transfer the fillets to a plate, spoon any remaining pan glaze over the top, and garnish with the 1 tbsp sesame seeds and sliced green onions. Serve immediately.