Rinse the 1 pound of dry pinto beans in a colander under cold running water, picking through them to remove any small stones or debris.
Place the rinsed beans in a large Dutch oven or heavy-bottomed pot and add 8 cups of cold water, ensuring the beans are covered by at least 2 inches of water.
Stir in the 6 ounces of diced salt pork, 1 finely chopped large yellow onion, 4 minced garlic cloves, 2 teaspoons ground cumin, 1 teaspoon dried oregano, and 1 bay leaf.
Bring the pot to a boil over high heat, then immediately reduce the heat to low to maintain a gentle simmer, covering the pot with a lid slightly ajar.
Simmer the beans for 2 to 2 1/2 hours, stirring occasionally, until the beans are very tender and the broth has thickened slightly. The beans should mash easily against the side of the pot when done.
Season the beans with salt to taste, starting with 1 teaspoon and adding more as needed, then remove and discard the bay leaf before serving.