Cut salmon into 2-inch cubes. Place cubes into a bowl or baking dish.
In a medium bowl, whisk together soy sauce, pineapple juice, rice vinegar, and brown sugar.
Pour mixture over the salmon and allow salmon to marinate for 30 minutes to an hour in the fridge.
Once the salmon is done marinating, heat a large skillet over medium heat. Add the olive oil until hot.
With tongs, transfer the pieces of salmon to the skillet. Brown on both sides, about 5-7 minutes total. Carefully flip with tongs so you don’t break the pieces apart. Reserve the marinade to make the teriyaki sauce later.
Remove the salmon from the skillet and set aside on a clean plate. Add onions and bell peppers to the skillet and cook for 2 minutes.
Add the broccoli, bok choy, sugar snap peas, and water chestnuts. Stir to combine. Cook for 3-5 minutes until bright green and slightly softened.
Meanwhile, whisk the cornstarch and water together in a small bowl.
Remove vegetables from the skillet. Pour in the sesame oil. Add the garlic and ginger. Cook 30 seconds, stirring so it does not burn.
Carefully pour the marinade into the skillet. Whisk in the cornstarch and water slurry until the sauce thickens, about 2-4 minutes.
Add the vegetables back into the skillet and stir to coat in the sauce. Top with the cooked salmon and gently stir to prevent mashing the pieces.
Serve over rice and garnish with sesame seeds.