Lots of dried bean recipes specify an overnight soaking
for the beans. You can shorten the total start-finish
elapsed time by using the quick soaking method, which
is anyway superior at removing the three indigestible
sugars (raffinose, stachyose and verbascose) that cause
flatulence, according to every good bean cookbook:
1. Bring enough water to cover the dried beans to 2-1/2
times the height of the beans to a boil; DO NOT SALT
THE WATER.
2. Add the beans, and immediately remove from heat.
3. Cover and let stand for 1 hour.
4. Drain the beans, DISCARDING the soaking water.
The beans are now ready for the subsequent preparation.
As noted elsewhere, when cooking the beans, you want to
delay the addition of acidic foods, usually tomato, until
the beans are mostly cooked. You also want to delay adding
salt. Both acid and salt prevent the beans from softening.