For the Dressing:
1/4 cup rice vinegar
2 tablespoons prepared Dijon mustard
1/2 teaspoon celery seed
freshly ground pepper to taste
For the Salad:
1 10-ounce bag baby spinach leaves
4 clementines or small tangerines, peeled and sectioned
OR 1 cup canned mandarin orange sections, drained
1 bunch green onions, white part only, sliced thin
1/2 pound mushrooms, sliced
1/2 cup chopped walnuts
Stir the dressing ingredients together.
Combine the salad ingredients in a bowl and toss with the dressing.