Whisk soy sauce, brown sugar, garlic, ginger, and rice vinegar in a small saucepan. Bring to a gentle simmer over medium heat for about 2–3 minutes.

Reduce heat to low and simmer sauce until it coats a spoon, about 4–5 minutes, stirring occasionally to prevent burning.

Pat salmon fillets dry with paper towels, season lightly with salt and pepper, then brush both sides with olive oil.

Heat a nonstick skillet over medium-high heat for 1–2 minutes until hot. Place fillets skin-side down and cook until edges turn golden brown, about 3–4 minutes.

Flip fillets and pour half the teriyaki glaze over them. Cook for 2–3 more minutes until internal temperature reaches 125–130°F and glaze is glossy.

Transfer salmon to a plate, loosely cover with foil, and let rest for 2 minutes.

Arrange salmon over rice or a fresh salad, drizzle remaining glaze, and sprinkle with toasted sesame seeds and sliced green onions.