Rinse quinoa under cold water.
In a pot, bring water to a boil. Add quinoa, reduce heat, cover, and simmer for 15 minutes.
While quinoa cooks, season salmon with salt and pepper. Heat olive oil in a pan over medium heat. Cook salmon for 4-5 minutes per side until done. Remove and set aside.
In the same pan, sauté onion and garlic until fragrant. Add bell pepper and cook until softened.
Add cherry tomatoes and cook for another 2 minutes.
Fluff quinoa with a fork and mix with sautéed vegetables.
Break salmon into chunks and gently fold into quinoa mixture.
Drizzle with lemon juice, season with salt and pepper, and garnish with parsley if desired.