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
Directions
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.
