Preheat oven to 425°F. Arrange cauliflower and onion on a large rimmed baking sheet; arrange chickpeas on a second large rimmed baking sheet. Whisk together oil, paprika, salt, and pepper in a small bowl. Divide evenly between baking sheets; toss well to coat.
Bake until vegetables are golden and tender and chickpeas are crispy, about 35 minutes. Transfer chickpeas to baking sheet with roasted vegetables, tossing well to combine. Let cool slightly, about 15 minutes. Transfer to an airtight container, and refrigerate until ready to serve.
Whisk together oil, tahini, mustard, honey, turmeric, salt, and pepper in a small bowl. Transfer dressing to an airtight container, and refrigerate until ready to serve.
