Put the sausage in a large (5-qt) thick-bottomed pot, such as a Dutch oven, and heat over medium low heat. Break up the large clumps of sausage and gently cook until lightly browned, rendering out the fat from the sausage.
If the sausage is relatively lean and doesn't produce much fat when you cook it, add a tablespoon of olive oil to the pot. Note that you are just trying to lightly brown the sausage, not cook it through. Remove sausage with a slotted spoon and set aside. You should have at least one tablespoon of fat or oil left in the pot, if not, add more.
Add the sliced onions to the pot and cook on medium heat until translucent, about 8 to 10 minutes. Add the minced garlic and cook a minute more.
Add the chopped tomatoes, stock, bay leaves, oregano, and pepper. Bring to a simmer on high heat, reduce the heat to low and maintain a simmer for about 15 minutes.
Add the chopped kale, chickpeas, and sausage to the soup. Cook for another 15 to 20 minutes, until the kale is tender. Add salt to taste.