Preheat the oven to 425ºF. Line a baking sheet with parchment paper for easy clean-up.
Add the vegetables (onion, bell pepper, broccoli, and green beans) to the lined baking sheet. Drizzle with avocado oil, season with salt & pepper, and lightly toss to coat the veggies. Arrange them flat on the baking sheet and transfer to the oven.
Roast the vegetables for 10 minutes.
Meanwhile, on the stovetop, combine the sauce ingredients in a saucepan and bring to a simmer. Continue to cook, stirring often, allowing the sauce to reduce and thicken. Turn the heat off once it reaches a consistency you prefer.
When the vegetables finish, move them to the sides of the pan to make room for the salmon. Drizzle the salmon with avocado oil and a sprinkle of salt & pepper.
Place the baking sheet back in the oven, and roast for 15 minutes longer to cook the salmon through. Once finished, drizzle the entire dish with teriyaki sauce.
Serve hot over riced cauliflower or a bed of greens.