Arrange orange slices in 2 (13 x 9-inch) baking dishes, and sprinkle evenly with dates.
Remove and discard giblets and necks from hens. Rinse hens with cold water; pat dry. Remove skin, and trim excess fat. Split hens in half lengthwise. Place hen halves, meaty side up, on top of dates.
Prepare paste: Place cilantro in a food processor; pulse 4 times or until coarsely chopped. Add cardamom, cumin, coriander, and garlic, and process until finely chopped. Pat cilantro mixture onto hens; arrange olives around hens.
Prepare marinade: Combine vinegar, wine, and honey; stir well with a whisk until well-blended. Place in refrigerator for up to two days, if desired.
Slowly pour marinade over hens. Cover and marinate in refrigerator 2 to 24 hours, basting once with the vinegar mixture.
Preheat oven to 350°.
Uncover hens, and bake at 350° for 1 hour and 25 minutes or until juices run clear, basting occassionally with the vinegar mixture. Shield wings with foil, if needed.