1. Preheat grill.
2. Slice off the tops of the tomatoes and cut away the inside , scooping out the inner flesh and seeds but keeping the outside intact.
3. Rub the outsides with olive oil and grill on both the top and the bottom, until just soft (about three minutes).
4. In a large bowl, place the couscous, boiling water, oil, and salt.
5. Cover and let sit for 10 minutes.
6. Fluff with a fork and add remaining ingredients.
7. Mix well until combined.
8. Spoon salad into the tomato “bowls” and serve warm or at room temperature.