Lightly coat inside of slow cooker with non-stick cooking spray. Reconstitute chiles by soaking in water for 20 minutes. Wearing gloves, cut chiles open and remove seeds and stems. Put chili skins in a small food processor along with garlic, oil, lime juice, salt, pepper, adobo seasoning, and paprika, and puree into a paste. Put paste into slow cooker along with chicken, and squish chicken around in the paste until thoroughly coated/saturated.
In a bowl, mix sweet potatoes, onion, and apple pie filling, and pour mixture over chicken. Cover and cook on low for 6-8 hours or on high for 4-5. Transfer chicken and veggies to serving dish and keep warm.
Transfer cooking liquid to a medium saucepan. Stir 3 tablespoons flour into 1/4 cup of water and add to saucepan. Cook over medium heat until mixture is thickened and bubbly, then cook and stir 1 minute more.
Serve chicken and veggies with rice and thickened sauce.