Bring the water to a boil for the couscous. Add a pinch of salt. Once the water is boiling, remove it from the heat, add the couscous, cover it, and let it sit for 5 minutes.
When the couscous is ready, mix in the canned tuna, the halved cherry tomatoes, a pinch of salt, the salad leaves, and fresh basil. Drizzle with lime juice and it’s ready to eat.