Up to 1 day ahead, prepare rabbit as directed.
To serve tostadas, heat 2 inches of oil in a frying pan to 360 degrees F. Fry tortillas, 1 at a time, until crispy, about 2 minutes (do not fold tortilla). Drain on paper towels and set aside.
In a saucepan, heat the rabbit in the reserved braising juices. Put a fried tortilla on each plate and top with a ladleful of black beans. Place the rabbit on top of the beans. In a bowl, lightly dress radishes, cabbage, and cilantro leaves with vinaigrette. Place a small mound of slaw on each tostada; top with salsa. Sprinkle with feta and pumpkinseeds and serve.
Preheat the oven to 425 degrees F.
Pull stems off of the chiles, leaving seeds inside. Place chiles in pie plate in a hot oven for 1 to 2 minutes until they smell fragrant to bring out flavor. Place in a bowl and add just enough hot water to cover. Soak for 1 hour. In a blender, puree chiles, oregano, garlic, cumin, and remaining salt and pepper. Strain through a fine sieve into a bowl and set aside.
In a wide frying pan, heat oil over medium-high heat. Season rabbit pieces with salt and pepper and saute until golden brown on each side, about 7 minutes. Remove and reserve rabbit. Add celery, carrot, and onion to pan and saute until just browned. Add the chile puree and cook, stirring, for 1 to 2 minutes to bring out the flavor. Add rabbit pieces to the pan and add just enough stock to cover. Bring to the boil. Reduce heat, cover and simmer until the meat is very tender. Let cool, then strain and reserve both sauce and meat. Pull meat from the bones being very careful not to miss any; discard skin and bones. Chill meat and sauce separately.
In a large pot, bring black beans to boil in water to cover by 2 inches. Add half the onion, the celery and the bay leaf. Reduce heat and simmer until beans are tender, 1 1/2 to 2 hours. Strain and reserve liquid.
In same pot, heat olive oil and add bell pepper, remaining onion, garlic, green onions, basil, cilantro, soy sauce, lemon juice, cumin, cardamom, salt, and pepper. When vegetables are tender, add the beans and the reserved cooking liquid and simmer until reduced by half. Beans can be prepared up to 2 days ahead and refrigerated. To use, ladle out amount desired and heat until warmed through.
Combine vinegar, lime juice, cumin, salt and pepper in a bowl and mix well. Whisk in the oil until emulsified. Set aside until ready to use.
Combine all ingredients and mix well, but gently. Do not mash avocados. Use immediately.