Place beans in medium bowl. Add enough cold water to cover by 2 inches; soak overnight. Drain.
Boil the beans with enough water and salt until done, about 1 hour (this can even be done in a pressure cooker). Strain and keep aside.
In a pot heat oil, add the onions and sauté until transparent, about 4 minutes, add the boiled beans, jalapenos, cumin and paprika and stir for some time.
Add the tomato puree and juice and simmer on a low heat for about 45 minutes until it becomes thick. Mash roughly with a wooden spoon.
In a bowl, toss together the tomatoes, the onion, the chili, the limejuice, the coriander, ketchup and salt to taste. Let the salsa stand for 30 minutes. The salsa can be made up to 4 hours in advance, kept covered and chilled. Let the salsa come to room temperature before serving.
With a large spoon spread out the beans in a ring on a large microwave-safe dinner plate, leaving clear about 4 inches in the center of the plate. That's where you're going to pile the chips.
Sprinkle the cheese, corn, cilantro, green onion, jalapenos and salsa over the beans. As you build up the layers, be sure to leave the space in the center of the plate empty.
Microwave on high for 2 minutes. Remove the plate from the microwave, pile the chips in the center of the plate, and sprinkle the remaining cheese over the chips. Return the plate to the microwave again on high for 1 minute, until the cheese has melted. . (Alternatively place in a baking dish and gratinate in the oven (250 C) or a salamander for 10 minutes or until the cheese has melted).
Garnish with a couple pinches of chopped cilantro. Serve hot.