Now that we're deep into summer and grilling has become second nature, take a break from chicken and burgers and splurge a little on fresh tuna. Here the delicious, meaty fish is smoky from the grill and topped with a luxuriously rich herbed cream. In place of the usual tossed greens and rice or potatoes, there is a couscous salad studded with diced tomatoes, carrots and cucumbers. Fresh citrus juices add a refreshing note to the vinaigrette for the salad and to the thirst-quenching drink that goes with the meal.