In bowl combine ground chicken, half of the pesto, the Parmesan, garlic, and salt. Shape into four 1/2-inch-thick oval patties (to fit bread).
Halve ciabatta horizontally. Brush cut side of ciabatta or both sides of Italian bread with olive oil; set aside (reserving any extra oil).
For a charcoal grill, place patties on greased rack directly over medium coals. Grill, uncovered, 10 to 13 minutes or until chicken is no longer pink (165 degrees F), turning once halfway through grilling. Top each patty with a mozzarella slice. Cover grill; grill 1 to 2 minutes more or until cheese is melted. Add bread and grill for 1 to 2 minutes per side or until toasted. (For gas grill, preheat grill. Reduce heat to medium. Place patties on grill rack over heat. Cover; grill as above.)
Arrange greens on toasted bread. Top with chicken patties and tomato slices. Stir any remaining olive oil into remaining pesto and drizzle over all. Sprinkle with coarsely ground black pepper. Makes 4 servings.