One option is to drain the beans into a large strainer and rinse with cold water. Then return the beans to the pot and bring to a boil with enough water to cover the beans. Rinse and repeat the process, as necessary, if the beans are still too salty.
My grandpa would add a patita de puerco (pig's foot) to his salty beans and would let them simmer for another hour or so. The patita de puerco absorbed some of the salt, while also adding extra flavor to the beans.
But my favorite remedy is super simple and highly effective...
Just add 2 or 3 potatoes, peeled and quartered/sliced/chopped, to the pot of frijoles and let simmer for about 15 minutes. (Add 1 to 2 cups of water to the beans, if necessary.) The potatoes will absorb some of the salt, and salvage your pot of frijoles. You can remove the potatoes and use them in some other dish. When my kiddies were little, they loved to eat those chopped cooked potatoes in a bowl of caldo de frijoles (bean broth).
Do you have any tips for how to salvage salty beans? Share your tips below in the comments!