Preheat the oven to 400ºF.  Chop the cauliflower into small florets and place them on a large baking sheet covered with parchment paper.  Slice the red onion into 1/4-inch strips and place them on the baking sheet.  Drizzle the cauliflower and onions with olive oil and season with a pinch or two of salt and pepper.  Toss the cauliflower and onions until coated in oil, salt, and pepper.

Roast the cauliflower and onions in the preheated oven for 20 minutes, then stir, return them to the oven, and roast for an additional 15-20 minutes, or until the cauliflower is tender and browned on the edges.  Remove tray from oven and set aside to cool slightly.

While the cauliflower and onions are roasting, make the lemon tahini dressing.  Add the tahini, water, lemon juice, garlic, cumin, cayenne (if desired) and salt to a blender.  Blend until smooth, then refrigerate until ready to serve.

Drain and rinse the can of chickpeas.  Add them to a non-stick skillet along with the olive oil, smoked paprika, cayenne (if desired) and a pinch of salt and pepper.  Stir and cook the chickpeas over medium heat for about five minutes, or until they sizzle and become slightly crispy.  Remove the chickpeas from the heat.

To build the salad, combine the roasted cauliflower and onions in a bowl with the spiced chickpeas and chopped greens.  Lightly drizzle the lemon tahini dressing over top, and toss to combine.  Serve warm or cold with the extra dressing on the side.