Chicken and Wild Rice Salad

From Gourmet Magazine June 2003

4 cups water
1 cup wild rice
1 1/2 teaspoons salt, or to taste
1/2 cup plus
2 tablespoons olive oil
1/4 cup Sherry vinegar
2 tablespoons Dijon mustard
1/2 teaspoon black pepper
4 cups cubed (1/2 inch) cooked chicken (about 1 3/4 lb)
2 celery ribs, cut into 1/4-inch-thick slices (2 cups)
1 medium red onion, finely chopped (1 cup)
2 Granny Smith apples, cut into 1/2-inch cubes

Bring water to a boil in a 2-quart heavy saucepan, then add rice and 1 teaspoon salt. Reduce heat to low and cook, covered, until rice is tender and most grains are split open, 1 to 1 1/4 hours. Drain well and cool.
Whisk together oil, vinegar, mustard, remaining salt (or to taste), and pepper.
Combine rice with remaining ingredients in a large bowl, then gently toss with vinaigrette.