Barbecued chinese chicken lettuce wraps

Chicken second courses

2 cups, 4 handfuls, fresh shiitake mushrooms 1⅓ to 1½ pounds thin cut chicken breast or chicken tenders 2 tablespoons light colored oil, such as vegetable oil or peanut oil Coarse salt and coarse black pepper 3 cloves garlic, chopped 1 inch ginger root, finely chopped or grated, optional 1 orange, zested ½ red bell pepper, diced small 1 small tin, 6 to 8 ounces, sliced water chestnuts, drained and chopped 3 scallions, chopped 3 tablespoons hoisin, Chinese barbecue sauce, available on Asian foods aisle of market ½ large head iceberg lettuce, core removed, head quartered Wedges of navel orange -- platter garnish