Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Slice the chicken breast into thin strips and chop the cauliflower, bell pepper, and red onion into uniform, bite-sized pieces.
In a large mixing bowl, whisk together the extra virgin olive oil, ground cumin, smoked paprika, turmeric, sea salt, and black pepper.
Add the chicken and vegetables to the bowl and toss thoroughly until every piece is well-coated in the spice mixture.
Spread the chicken and vegetable mixture across the prepared baking sheet in a single, even layer to ensure even roasting.
Roast for 20 to 25 minutes, stirring halfway through, until the chicken is fully cooked and the vegetables are tender with slightly charred edges.
While the chicken is roasting, whisk together the Greek yogurt, tahini, and lemon juice in a small bowl until the sauce is smooth and creamy.
Plate the roasted chicken and vegetables and finish the dish with a generous drizzle of the tahini-yogurt sauce.