Heat the olive oil in a large, deep frying pan and add the onion and pepper. Season to taste with salt and pepper and cook over a medium heat for 10 minutes until the onion is softened but not coloured. Add the chorizo, paprika and garlic and cook a further 5 minutes, then add the tomatoes, and cook, stirring occasionally, for 15 minutes. Stir through the black beans and cook a final 2 minutes.
Meanwhile, heat 1/4 cup Olive oil in a separate frying pan and fry the corn tortillas for 1-2 minutes each side, until golden, and drain well on paper towels. Wipe out the pan and fry the eggs (or poach the eggs separately) and serve the tostadas (fried tortillas) loaded with the tomato, chorizo and black bean sauce, eggs, avocado, green chilli, coriander and pumpkin seeds.