Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Place the cauliflower florets and drained chickpeas on the sheet, tossing with the olive oil, ground cumin, and half of the sea salt and black pepper until evenly coated.
Roast for 20-25 minutes, tossing halfway through, until the cauliflower is tender and the chickpeas are slightly crispy.
While the vegetables roast, season the chicken breast with the remaining salt and pepper, then grill or pan-sear over medium-high heat for 6-7 minutes per side until cooked through.
In a small bowl, whisk together the tahini, lemon juice, and water until the mixture reaches a smooth, pourable consistency.
Slice the cooked chicken into bite-sized pieces and combine in a large mixing bowl with the roasted vegetables and freshly chopped parsley.
Drizzle the lemon-tahini dressing over the salad and toss gently to ensure every ingredient is lightly coated before serving.