For the Sauce:

1. In a small saucepan, combine all ingredients except for optional cornstarch and water. Over medium heat, bring the mixture to a simmer for about 3 minutes.
2. If you like your sauce thick and need about 1.5 cups, use the cornstarch slurry to thicken it. Otherwise, simmer/boil the mixture down until you get your desired consistency (thick but drippy). Boiling down will reduce the amount of sauce.
3. Optional cornstarch slurry: In a small bowl combine cornstarch and water and whisk until combined. Slowly pour the slurry into the mixture, using the whisk to stir frequently as you pour. Let it come together another minute or two. If it gets too thick, add more water to loosen.

For the Salmon:

1. Preheat oven to 350 degrees, and if you haven't already started the rice, do so now. On a parchment lined baking sheet with walls, place salmon slices in the middle of the tray and layer mushrooms, peppers, and bok choy in all around the salmon.
2. Generously coat the salmon with the teriyaki sauce and sprinkle sesame seeds on top of each salmon filet.
3. Pour oil over veggies and sprinkle veggies with a heavy pinch of salt. Gently mix, careful not to disturb the salmon.
4. Place sheet pan in the oven, for about 12-15 minutes, stirring veggies halfway through. Feel free to mix some of the teriyaki sauce to lightly coat the veggies at the halfway point. Bake until the center pieces of salmon have turned fully opaque up the sides. You can gently poke/squeeze the salmon and it should feel bouncy and tender.
5. Fluff the rice and add the rice vinegar for flavor and a little sticky texture.
6. In 4 individual bowls, layer 1 cup of rice, ¼ of the veggies, and 1 piece of salmon. Drizzle teriyaki sauce and garnish with another sprinkle of sesame seeds if you so desire and top with sliced green onions.