Mix salt, garlic powder, thyme and pepper; rub over turkey breasts. Place in a 5- or 6-qt. slow cooker. Pour water around turkey. Cook, covered, on low 3-4 hours (a thermometer inserted in turkey should read at least 165°).
Remove turkey from slow cooker; tent with foil. Let stand 10 minutes before slicing.
Meanwhile, in a large saucepan, combine compote ingredients. Bring to a boil. Reduce heat to medium; cook, uncovered, stirring occasionally, until mixture is slightly thickened and apples are tender, 15-20 minutes. Serve turkey with compote.