Pressure cooking beans is easy. I cannot tell you the exact timing except that black, pinto, white and kidney beans cook in about 4 to 6 minutes at pressure with a natural pressure release. —TheVeggieQueen
dry beans, rinsed and picked through. soaked overnight,
Drain soaking liquid from beans. Put the beans in the pressure cooker with the water and kombu. Bring to high pressure and lower the heat to maintain high pressure for the allotted time. Let the pressure come down naturally.
Quick Soak Method, as a way to presoak:
Put about 3 inches of water above the beans and bring to a boil for 1 minute. Turn off the heat, cover and let sit for 1 hour. Dump the water and then start cooking.