Wipe the salmon fillets dry with paper towels.
Whisk soy sauce, rice vinegar, brown sugar, garlic, ginger, black pepper, and cornstarch until the sugar dissolves.
Reserve about 1/2 cup marinade, place salmon skin-side up in the rest, and marinate 10 to 15 minutes.
Preheat the air fryer to 400°F. Place salmon skin-side up on parchment and air fry 6 to 7 minutes.
Heat the remaining marinade on medium until thick and saucy.
Turn salmon skin-side down, brush with glaze, and air fry 2 to 3 minutes more, to 140°F to 145°F internally.
Remove, glaze as desired, and garnish with sesame seeds and sliced green onions.