Sprinkle chicken with 1/2 teaspoon salt and 1/2 teaspoon black pepper. Coat both sides of each chicken breast half with 1 1/2 teaspoons mayonnaise. Place chicken on grill rack coated with cooking spray. Grill for 3 minutes on each side or until done. Brush 1 1/2 teaspoons chutney over each chicken breast half. Place bread slices on grill rack, and grill for 1 minute on each side or until golden. Spread 1 tablespoon chutney onto each of 4 bread slices, and top each serving with 1/2 cup arugula and 1 chicken breast half.