Heat grill or grill pan to medium-high. Rinse tomatoes and gently pat dry. Cut each tomato into 1/4-inch-thick slices, starting from bottom of tomato.
Meanwhile, grill sausages for 12 to 15 minutes, turning frequently, until cooked through.
Place greens on a large platter. Cut mozzarella into thin slices. Decoratively fan tomato slices, mozzarella and basil over greens, alternating varieties of tomatoes for contrast.
Drizzle salad with vinegar and olive oil, and sprinkle with salt and pepper. Serve alongside grilled sausages and, if desired, Italian bread.
Premio fresh Italian chicken sausage pairs well with this salad; $5 at Sam's Club and Costco stores.