Preheat oven to 400° F and line a baking sheet with parchment paper. If making bites, chop into 1" cubes. Otherwise leave it as a filet, removing the skin if needed.
Combine tamari (or soy sauce), remaining water, honey, brown sugar, ginger, garlic and rice vinegar in a pan over medium heat. Combine 1 ½ Tablespoons corn starch with the 1 ½ Tablespoons water to make a slurry. Stir into the mixture. Bring to a boil, and boil about 1-2 until the mixture thickens and becomes translucent. See photos above for a visual guide. Remove from heat and allow to cool slightly. The sauce will thicken a lot more as it cools.
Place salmon in a bowl and drizzle ¾ of the teriyaki sauce over top. Toss to combine then place on the parchment lined baking sheet. Make sure the salmon (filets or cubes) pieces aren't touching each other. Bake filets for 12-16 and cubes 10-13 minutes until cooked through and flaky. Salmon is done at 140°F. Brush with remaining teriyaki. Serve and enjoy!
Notes
For a sweeter teriyaki sauce, increase the brown sugar by an additional 1-2 Tablespoons.
To make in the air fryer: Preheat air fryer to 400°F. Add salmon and cook cubes for 5-7 minutes and filets for 6-8 minutes, or until cooked through and flaky.