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While beans are often canned with calcium chloride to keep cell walls strongs and salt for flavor, all of the starch that leaches into the water is inherent in the beans. It just needs to be let out through the cooking process.

The USDA has a guide at https://nchfp.uga.edu/how/can_04/beans_peas_shelled.html

which recommends either a 12 hour soak or a 2 minute boil followed by a 1 hour soak; throwing away the first water and bringing to a boil in new water for 30 minutes. The first water soak is important to remove toxins from some bean varieties, as well as start the hydration process.

The second set of water, in which the beans have boiled for 30 minutes, will have a fair amount of starch dissolved in it, but not as much as it will later. If you don't want to properly can the beans, you can store them in the water in a refrigerator for several days to get the released starch.