Soak the beans overnight in cold water, changing the water once. Rub the beans between the palms of your hands to free the outer skins, which should float to the surface. Scoop off the skins and discard. Drain the beans. Puree the beans and onion in a food processor. Season with salt and pepper and chili. Using 2 soup spoons, form the bean mixture into small egg shapes. Press a dried shrimp into the center of each one, and press the bean mixture round to secure it. The shrimp should still stand proud. Heat the oil to 350 degrees and fry the fritters in small batches until golden brown all over. Remove with a slotted spoon and drain on paper towels. Keep warm in a low oven until they are all fried.