Preheat the oven to 425°F. Toss the cauliflower florets and chickpeas with 2 tablespoons of olive oil, cumin, smoked paprika, chili flakes, salt, and black pepper in a large bowl until evenly coated. Spread the mixture on a baking sheet in a single layer and roast for 25 minutes, stirring once halfway through, until the cauliflower edges turn golden.

While the vegetables roast, heat a nonstick skillet over medium heat. Add the halloumi slices and cook for 2 to 3 minutes per side until golden brown. Remove from the heat and set aside.

In a large serving bowl, combine the arugula and cherry tomatoes. Drizzle with the remaining tablespoon of olive oil and the lemon juice, then toss gently. Top with the roasted cauliflower and chickpeas, add the grilled halloumi, and finish with the chopped parsley.