The morning you want to make the Samgyetang, wash the rice and soak it in a bowl full of cold water. Rub each hen with a tablespoon of kosher salt, both inside and out.
When you're ready to start cooking, drain the rice and mix it with the pine nuts. Add a ginseng root, garlic clove, jujube, and chestnut into the cavity of each hen, then split the rice between the two hens. Add another garlic clove, jujube, and chestnut to each chicken, then cut a small slit into the flap of skin just above each drumstick and thread the end of each drumstick through both flaps as shown in the photo below. You could also use a toothpick to "stitch" the opening shut, you just want to keep the opening closed so the stuffing doesn't all fall out.
Add the chicken stock and remaining ginseng root, garlic, and jujubees to a pot that's just big enough to hold both hens. Bring to a boil, then carefully add both hens. Return the soup to a boil then cover and turn the heat down to low and simmer for one hour.
Serve the Samgyetang in a small pot or stone bowl along with the soup, then garnish with the scallions. Give each person a small plate of salt that can be added to the soup to taste, or be used to dip the chicken meat into.