Rinse the quinoa under cold water using a fine mesh strainer.
In a medium saucepan, combine the rinsed quinoa and 2 cups of water. Bring to a boil over medium-high heat.
Once boiling, reduce heat to low, cover, and simmer for 15 minutes or until the water is absorbed and quinoa is tender.
Remove the quinoa from heat and let it sit covered for 5 minutes, then fluff with a fork.
While the quinoa cooks, preheat the oven to 400°F (200°C).
In a small bowl, mix salt, black pepper, garlic powder, and paprika.
Pat the salmon fillets dry with paper towels and rub them with olive oil.
Sprinkle the seasoning mixture evenly over both sides of the salmon fillets.
Place the salmon fillets skin-side down on a baking sheet lined with parchment paper.
Bake the salmon in the preheated oven for 12-15 minutes, or until the salmon flakes easily with a fork.
While the salmon bakes, heat butter in a large skillet over medium heat.
Add the sliced onion and cook for 2 minutes until slightly softened.
Add the minced garlic, broccoli florets, and sliced red bell pepper to the skillet.
Sauté the vegetables for 6-8 minutes, stirring occasionally, until tender-crisp.
Season the vegetables with salt and black pepper to taste.
Remove the salmon from the oven and drizzle with fresh lemon juice.
Sprinkle chopped fresh parsley over the salmon and vegetables.
Serve the baked salmon fillets over a bed of quinoa with the sautéed vegetables on the side.