Preheat the air fryer to 350 degrees F.

Prepare the teriyaki sauce:

1. In a small saucepan, combine the soy sauce, 3/4 of the water, garlic, ginger, honey, and brown sugar.
2. Cook over medium heat, whisking until the sugar has dissolved and the sauce begins to thicken.
3. In a separate bowl, mix the corn starch with the remaining cold water and whisk to create a slurry.
4. Slowly add the corn starch slurry to the sauce, continuously whisking until sauce is thick with a glossy consistency (about 2 minutes).
5. Remove from the stove and let cool. Set some of the sauce aside for drizzling on top of the cooked fish.

Marinate the salmon:

1. Place the salmon filets in a shallow dish, or resealable plastic bag. Pour the teriyaki sauce over the fish making sure all of the fish is well coated.
2. Place the fish in the refrigerator for 15-20 minutes to let marinate.

Air fry the salmon:

1. After removing the salmon from the marinade, place the fish in the air fryer (make sure to first spray the air fryer with cooking spray or layer with parchment paper).
2. Air fry the salmon skin side down for about 10 minutes, or until the fish reaches your desired temperature. The salmon should be flaky and cooked through.
3. To create a caramelized glaze, brush the reserved teriyaki sauce over the fish during the last few minutes of cooking.

Garnish and serve:

1. Sprinkle the salmon with the toasted sesame seeds and sliced scallions.
2. If desired, drizzle the remaining teriyaki sauce over the fish.
3. Serve with a side of steamed rice and your favorite greens.