Bring the water to a boil. Add 1 tablespoon olive oil and a generous pinch of salt. Stir in the couscous, cover the pot, remove from the heat and let sit for 15 minutes. Remove the lid and fluff with a fork.
Meanwhile combine the tomatoes, ⅓ cup olive oil, basil, garlic, salt and pepper in a medium-sized bowl.
If you want a warm salad, turn the couscous into a large bowl, pour the tomato mixture over, toss to combine and serve right away. Or, for a room temperature salad, cool the couscous to room temperature by spreading it out on a rimmed baking sheet, then turn into a bowl and toss with the tomato mixture.
Notes
The more colors you can work in, the more dazzling the dish will be. You can also use cherry or grape tomatoes, and instead of chopping them cut them in half, or even quarters if they are on the larger side.