1. Sprinkle chicken with 1/2 teaspoon salt and 1/8 teaspoon black pepper. Heat oil in a large skillet over medium-high heat. Add chicken to pan; cook 2 minutes on each side or until browned. Place chicken in an electric slow cooker. Add garlic to pan, and sauté 30 seconds, stirring constantly. Add wine, scraping pan to loosen browned bits; cook 30 seconds. Place wine mixture in cooker. Add tomato paste, crushed red pepper, and tomatoes to cooker. Cover and cook on HIGH 4 hours. Stir in remaining 1/2 teaspoon salt, remaining 1/8 teaspoon pepper, olives, and parsley.
Add capers along with the olives, parsley, and seasoning for a more briny flavor, if you like. The parsley goes in last to keep its flavor and color intense.