For the tostadas:
Bring corn oil to 320 degrees or medium high heat. Fry tortillas in oil for three to five minutes or until golden brown. Season with salt and drain on paper towels.
For the beans:
Saute chorizo, garlic and onion over medium heat for 10 minutes. Add beans and cook over low heat for 10 minutes. Combine in a food processor and puree.
For the cabbage slaw:
Combine all ingredients and season with salt.
Top tostada with beans and cabbage slaw. Consider topping the tostada with other ingredients such as ceviche.