Place the couscous in a bowl and add enough warm water to cover by 1 cm (1/2 inch). Mix in the salt and leave the couscous to absorb the water for 20 minutes.
Meanwhile, heat 3 tablespoons of the oil in a large frying pan and cook the onions and two-thirds of the chilli over a medium heat, stirring, for 4–5 minutes until softened. Add the chickpeas and tomatoes and cook over a high heat, stirring occasionally, for 3 minutes until the chickpeas are heated through and the tomatoes are softened but still retaining their shape.
Meanwhile, mix the remaining olive oil and chilli with the herbs in a shallow bowl. Add the haloumi slices and toss to coat. Place the haloumi slices on a grill rack lined with foil and cook under a hot grill for 2–3 minutes until browned in places.
Stir the couscous into the chickpea mixture and cook for 1 minute to heat through. Serve piled on to warmed serving plates, topped with the haloumi slices.