Chicken Lettuce Wraps

Name: Chicken Lettuce Wraps
Ingredients: 6 large dried Chinese mushrooms; Drizzle of extra-virgin olive oil; 1/2 large onion, peeled and finely chopped; 2 pounds lean ground chicken; 3 tablespoons mirin or white wine; 1 tablespoon sesame oil; 1 tablespoon sesame seeds; 1 tablespoon oyster sauce; 1 tablespoon light soy sauce; One 8-ounce can water chestnuts, chopped; 1 clove garlic, peeled and crushed; 6 spring onions (scallions), chopped; 2 to 3 tablespoons plum sauce; 2 to 3 heads radicchio, leaves separated