In a small bowl, combine salad oil, white wine vinegar, garlic, Dijon mustard, oregano leaves, salt , and pepper, set aside. In a salad bowl, mix together cooked bulgur, dressing, mushrooms, and olives. Cover and refrigerate at least 1 hour or overnight. Bulgur cooking directions:: in large saucepan bring 4 1/2 cups of water to boil. Stir in bulgur, reduce heat to medium and cook, covered, for 10 minutes. Stirring occasionally.