Rinse beans and cover in large pot with water, letting soak for 8 hours, and then drain.
Preheat oven to 350°F.
Sprinkle pork roast with 1 teaspoon salt and pepper. Rub surface of roast with mixture.
Heat an oven-safe pot over medium-high heat and coat with cooking spray.
Add roast to the pan and cook for 15 minutes, turning to brown on all sides. Remove roast from the pan.
To the same pan, add onions, and sauté until tender. Return roast to the pan.
Add remaining ½ teaspoon of salt, beans, 5 cups of water, and optional dried sage to the pan; bring to a simmer. Cover and bake in pre-heated oven for 2 hours.
Add dried cranberries to pan; bake an additional 30 minutes. Remove and discard sage springs. Remove roast from pan and shred with two forks.