In an 8- to 10-inch frying pan over medium heat, shake the walnuts until they are lightly browned, about 5 minutes. Pour from pan.
In a wide salad bowl, mix vinegar, oil, and lemon peel. Add apricots and spinach leaves, and mix to coat fruit and greens with dressing. Sprinkle salad with the nuts and cheese. Season to taste with pepper.