Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Slice the seitan into thin strips and chop the broccoli and red bell pepper into bite-sized pieces.
In a large bowl, toss the seitan, broccoli, and peppers with olive oil, sea salt, black pepper, and smoked paprika until evenly coated.
Spread the mixture in a single layer on the prepared baking sheet and roast for 15 to 18 minutes until the vegetables are tender and the seitan is slightly crisp.
While the vegetables roast, prepare the dressing by whisking together the tahini, lemon juice, tamari, and minced garlic in a small bowl.
Add a teaspoon of warm water at a time to the dressing until it reaches a smooth, pourable consistency.
Place the warm cooked quinoa in the base of a serving bowl.
Top the quinoa with the roasted seitan and vegetable mixture, then drizzle the creamy tahini sauce over the top before serving.