Sort beans and rinse thoroughly. Add beans and 8 cups water to a large pot. Bring to a full boil and boil for 2 minutes. Remove from heat, cover and allow to soak for an hour. Drain and rinse again.
Return beans to pot and cover with 6 cups water. Stir in the onion and the diced ham. Simmer with a lid slightly tilted (ajar) for 1 ½ to 2 hours or until desired tenderness. Salt and pepper to taste. Garnish with green onion.