Gently mix the chickpeas, tomato, parsley, lemon zest and juice, sumac and olive oil in a large bowl. Set aside to marinate.
Place the cauliflower on a large roasting tray, drizzle with olive oil and season to taste. Bake for 20 - 25 minutes until tender and brown and crispy around the edges.
Slice the pita bread into wedges or strips and place on a separate tray in the oven for the last 5 minutes of cauliflower cooking time.
Add the cauliflower to the chickpea mixture and toss gently to combine.
To serve, arrange the salad, pita and hummous on plates as shown above.