Spinach Salad with Mandarin Oranges

1 package (10 oz.) spinach
1 cucumber, sliced
1 can (11 oz.) mandarin oranges, drained
1 or 2 green onions, chopped
1/2 pound fresh mushrooms, chopped
1 large avocado, diced
1/2 to 1 pound cherry tomatoes, cut in half
1/2 teaspoon grated orange peel
1/2 cup frozen orange juice concentrate
1/2 cup salad oil
2 tablespoons sugar
2 tablespoons cider vinegar
1 tablespoon lemon juice
1/2 teaspoon salt

Wash, stem, and drain spinach. In large salad bowl, toss together spinach, cucumber, oranges, green onions, mushrooms, avocado, and tomatoes. Combine remaining ingredients in blender or food processor and blend thoroughly. Chill and serve over salad. (Makes 10 servings.)