how to cook half a cup of pinto beans?

Open a can of pinto beans. Measure out 1/2 cup and put in a saucepan. Add some of the liquid from the can and heat over low heat until hot. Cover the pot if you want them to cook faster.

If you are referring to dried pinto beans, soak the beans overnight. Pour off the water and add enough water to cover the beans by and inch. DO NOT ADD SALT. Bring the pot of beans to a boil, immediately turn the heat down so the beans are simmering, cover the pot and cook until done. This could take about an hour or more depending on how old the beans are. Now if you are only want a 1/2 cup of cooked dried beans, use 1/4 cup of dried beans and follow the same procedure.