Preheat the oven to 400°F. Line a large baking sheet with parchment paper.
Place all of the cauliflower florets on the lined baking sheet. In a small bowl, whisk together the olive oil, lime juice, chipotle chili powder, garlic powder, chili flakes (if using), salt, and pepper. Pour this mixture over the cauliflower and then toss with your hands to evenly coat all of the pieces.
Spread the coated cauliflower out in a single layer on the baking sheet and then slide it into the oven. Set a timer for 20 minutes. When the timer goes off, remove the cauliflower from the oven and give it a toss with a spatula. Return the cauliflower to the oven for another 15 minutes.
While the cauliflower is roasting for its last 15 minutes, make the tahini glaze. In a small bowl, whisk together the tahini, maple syrup, lime juice, olive oil, salt, and pepper. Then, add the water and slowly whisk it together (to avoid splashing) until combined. The resulting mixture should be fluid but thick, kind of like a creamy ranch-style salad dressing consistency.
Once the cauliflower is done baking for the second increment of 15 minutes, it should be evenly deep golden brown on all sides and tender. Remove it from the oven and pour the tahini maple glaze over top. Using a spatula, carefully and quickly toss the cauliflower to evenly coat it in the glaze. Place it back in the oven for another 3 minutes or so, just to heat through.
Top the glazed cauliflower with the chopped cilantro and sesame seeds. Enjoy immediately!