For the beans: Add the beans, onion, bay leaf, and garlic to a large pot filled with cold water until completely covered. Cover and bring to a boil, then reduce the heat and simmer for 2 hours, stirring occasionally, or until softened. Drain the beans and discard the vegetables. Melt the duck fat in a pot, add the cooked beans and use a stick blender to blend until smooth. Alternately, transfer to a blender to puree, then add back to the pot. Season with salt; keep warm.
For the salsa cruda: In a blender puree together the tomatillos, serrano, jalapeño, cilantro, onion, garlic, lime juice, fish sauce and canola oil until smooth. Store in an air-tight container in the fridge for up to 2 days.
For the migas: In a large sauté pan, cook the chorizo over medium-high heat for 3 to 4 minutes, until the fat is released. Add the eggs, and crushed tortilla chips, mixing for 2 to 3 minutes, until combined. Set aside.
Warm the tortillas in a comal or large skillet. Spoon a tablespoon or so of the beans onto each tortilla. Divide the chorizo and egg mixture on top. Garnish with the salsa cruda, avocado, queso fresco, and cilantro leaves. Serve with lime wedges and freshly ground black pepper. Enjoy!