Italian Chicken Salad

For croutons
4 cups (1/2-inch) cubes Italian bread (from a 1/2-lb crusty round loaf)
2 tablespoons extra-virgin olive oil
1/4 teaspoon salt

For vinaigrette
1/4 cup red-wine vinegar
2 teaspoons Dijon mustard
2 tablespoons finely chopped shallot
1 teaspoon sugar
1/4 teaspoon salt
1/8 teaspoon black pepper
1/2 cup extra-virgin olive oil

For salad
2 cups coarsely shredded cooked chicken (1/2 lb; from a rotisserie chicken)
1 cup bocconcini (small fresh mozzarella balls; 6 oz)
2 hearts of romaine (3/4 lb total), torn into bite-size pieces
1 (8-oz) jar roasted red peppers, rinsed, drained, and cut lengthwise into 1/4-inch-wide strips
1 cup assorted marinated brine-cured olives (5 oz)

Make croutons:
Put oven rack in middle position and preheat oven to 400°F.

Toss bread cubes with oil and salt in a large shallow baking pan and spread in 1 layer. Bake, turning over once, until golden and crisp, about 8 minutes. Cool in pan on a rack.

Make vinaigrette and begin preparing salad while croutons bake:
Whisk together all vinaigrette ingredients except oil in a small bowl until combined. Add oil in a slow stream, whisking until emulsified.

Toss chicken and bocconcini together with 1/4 cup vinaigrette in a bowl and let stand 10 minutes to allow flavors to develop.

Make salad:
Toss together romaine, red peppers, olives, chicken and bocconcini mixture, croutons, and remaining vinaigrette in a large bowl until combined.