Place the ancho chilies in a small bowl, cover with near boiling water and set aside. (boiling is fine too, just pull it off right when the bubbles start)
In a large saucepan set to medium heat (or directly on the hot grill) add 1 tablespoon olive oil and the onions. Let the onions soften (around 5 minutes), then add garlic, and mix together for one minute. Add the cumin, stock, wine, and miso.
Drain the chilies and cut in half to remove seeds and core. Chop the chilies and add to the sauce. Next add the prunes and the grilled chicken pieces. Return the pot to the grill (or leave on the stovetop). Cover and simmer for 20 minutes, basting 1-2 times to get some of those delicious juices on the chicken. Remove from heat.
Serve by placing a chicken piece on a plate and top with loads of that tasty sauce with the chilies and prunes.