Preheat oven to 400°F and line a baking sheet with parchment paper.
Toss the broccoli florets, sliced red bell pepper, and zucchini with olive oil, garlic powder, sea salt, and black pepper.
Spread the vegetables in a single layer on the baking sheet and roast for 15-18 minutes until tender and slightly charred.
While vegetables roast, season the salmon fillet with a pinch of salt and pepper.
Heat a non-stick skillet over medium-high heat and sear the salmon for 4-5 minutes per side until cooked through and golden.
In a small bowl, whisk together the lemon juice and tahini until smooth.
Assemble the bowl by placing the cooked quinoa at the bottom, followed by the roasted vegetables and the pan-seared salmon.
Drizzle the lemon-tahini dressing over the entire bowl and serve immediately.