Pour the dried red kidney beans into a large bowl. Add enough cold water to completely cover the beans by about 1 inch. Leave the bowl on the counter for the beans to soak overnight. When ready to use, drain the beans and set aside.
In a large pot over medium heat, add one tablespoon of oil and brown sausage for about 5 minutes or until a slightly brown color develops. Then, transfer sausage to a bowl and set aside, reserving the sausage grease in the pot.
Add the diced peppers, onions, and celery to the pot with the sausage grease. Sauté the vegetables for about 15 minutes, stirring often and using your spoon or spatula to scrape up the fond (brown bits) from the bottom of the pan.
Add the minced garlic to the pot with the vegetables. Sauté the garlic and vegetables together for about 3-4 minutes.
To the pot with the vegetables and garlic, add the following: chicken broth, water, drained kidney beans, ham hock, bay leaves, and Cajun seasoning. Mix together briefly, and bring to a boil over medium heat.
Once the liquid comes to a boil, cover the pot with a lid and reduce the heat to simmer for about 2½-3 hours. About 2 hours into the simmering time, check the thickness of the beans. If needed, leave the lid off for the remaining 30 to 60 minutes of simmering time for some of the liquid to evaporate and the beans to thicken.
Also at the 2 hour mark, use a slotted spoon to remove about ⅓ to ½ of the beans from the pot and transfer to a bowl. Use a fork to mash the beans up to a smooth, thick consistency. Then, add the mashed beans back to the pot and stir well. This helps to thicken the red beans mixture.
When there is about 20 minutes of simmering time remaining, add the sausage back to the pot. Continue to simmer for 15-20 minutes, stirring often. Total simmering time should be about 2½-3 hours.
Ladle red beans and sausage over a bed of cooked white rice. Garnish with sliced green onions and a few dashes of hot sauce if you wish. Enjoy!