Rainy day? You can also use the broiler for this salad. Simply place tuna on the broiler pan rack, then broil with tops 4 to 6 inches from heat using times in recipe as a guide.
The best place to find fresh mozzarella is at the deli in your grocery store. They may even be willing to slice it for you.
Line the serving plate with large fresh spinach leaves before you arrange the tomatoes. The spinach will provide a pretty layer and is a nice addition to the salad.