1. In a small bowl, combine bulgur and 1 1/2 cups boiling water. Let stand until bulgur is tender to bite, about 15 minutes.
2. Meanwhile, stack spinach leaves and cut into 1/4-inch-wide strips.
3. Place spinach, onions, dill, and cheese in a wide bowl. Pour bulgur into a fine strainer and press out the excess water. Add bulgur to bowl with spinach.
4. Mix vinegar and oil. Add to salad and mix. Season with salt and pepper to taste.