Rinse the quinoa thoroughly under cold water.
Add quinoa, salt, and water to a saucepan.
Bring to a boil over medium-high heat.
Reduce heat, cover, and simmer for 15 minutes.
Remove from heat and let sit, covered, for 5 minutes.
Fluff the quinoa gently with a fork.
Preheat the oven to 425°F (220°C).
Arrange the onion, peppers, sweet potato, and squash on a large baking sheet.
Drizzle with olive oil and season with salt, pepper, garlic powder, and oregano.
Toss until evenly coated.
Roast for 30 minutes.
Flip the vegetables and broil for 5 minutes until lightly caramelized.
Divide the quinoa into four bowls.
Top with the roasted vegetables.
Garnish with parsley and drizzle generously with tahini sauce.
Enjoy this Roasted Vegetable Quinoa Bowl immediately while warm.