Place the tomato juice in a saucepan over medium heat and bring to just below boiling point, then remove from the heat. Add the couscous and 1 tablespoon of the oil, then season with salt and pepper. Cover with a tea towel and stand for 10 minutes.
Place a chargrill or frypan over high heat. Brush the salami with a little extra oil and cook for 30 seconds each side until starting to crisp. Drain on paper towel.
Combine the lemon zest and juice, chilli flakes and remaining 1 tablespoon oil in a bowl and season with salt and pepper.
Use a fork to fluff the couscous grains. Add the rocket leaves, tomato, bocconcini, pepperoni and the dressing and toss to combine. Pile the salad onto a serving platter.