Cut the salmon into 1-inch (2.5 cm) cubes. In a medium bowl, mix salmon with teriyaki sauce. Set aside.
¼ cup teriyaki sauce
Slice the onion and red bell pepper (yellow pepper too if using). In a large skillet, heat 1 tablespoon oil over medium-high heat. Add salmon pieces, spacing them out in the pan.
1 pound salmon fillet, 2 tablespoons vegetable oil, 1 small red onion, ½ red bell pepper, ½ yellow bell pepper
Cook for about 2–3 minutes per side until golden brown. Remove from the pan. Add the remaining 1 tablespoon oil to the same pan. Add onion, peppers, zucchini, and broccoli.
½ small zucchini, green onions, 1 cups frozen broccoli florets
Cook for 3 minutes, stirring, until just tender-crisp. Return the salmon to the pan, gently toss with the vegetables, and heat for 2–3 minutes more until warmed through and coated in sauce.