Peel and grate the garlic into a large bowl. Finely grate the zest from the lime. Juice half of it. Add the juice and half the zest to the bowl. Pour in 1 tbsp oil. Season with a little salt and pepper.
Add the chicken to the bowl. Toss to coat in the marinade. Set aside to marinate for a few mins. If you’re using wooden skewers, place them in a dish of water to soak.
Peel and finely slice the onions. Heat a deep frying pan or wok for 1 min. Add 1 tbsp oil and the onions with a pinch of salt. Cook on a mediumlow heat for 10 mins till soft and sticky, stirring now and then. For the final 1 min, add in 1 tsp of the cumin seeds.
While the onions cook, heat your grill to its highest setting. Thread the marinaded chicken and the whole cherry tomatoes onto skewers. Lay on a foil lined baking tray. Slide under the grill and cook for 10 mins, turning now and again. The chicken should be cooked through and slightly charred.
Tip the couscous into the pan with the onions. Pour in 300 ml boiling water and stir. Bring to the boil. Cover and turn off the heat. Let it sit for 5 mins till all the water is absorbed and the couscous is soft.
Roughly chop most of the rocket and stir it into the couscous with the remaining lime zest. Taste and add more salt and pepper if it needs it.
Serve the grilled chicken kebabs with the couscous, the remaining rocket on the side and the remaining lime sliced into wedges for squeezing.