Halve peppers and remove seeds. Rub with oil; sprinkle with salt and pepper. Broil 4 in. from the heat until skins blister, about 4 minutes. Immediately place peppers in a bowl; cover and let stand for 15-20 minutes. Peel off and discard charred skin. Coarsely chop peppers.
In a large bowl, combine the peppers, spinach, onion, mushrooms, tomato, celery and olives. In a small bowl, combine the vinegar, oil and honey. Pour over vegetables and toss to coat. Sprinkle with blue cheese and parsley; gently toss to coat. Serve with a slotted spoon.
Wear disposable gloves when cutting hot peppers; the oils can burn skin. Avoid touching your face.