Set oven to 400 degrees F.
Toast walnuts in a pan over high heat for about 3 minutes.
Combine walnuts and beans in a food processor, pulsing until mixture is fully incorporated but not mushy.
Saute onions and garlic with 1 tablespoon olive oil over medium heat for about 2-3 minutes.
Add bean mixture, tomatoes, and spices, and stir to incorporate. Cook for about 5 minutes.
While beans are cooking, brush both sides of corn tortillas with remaining oil.
Place tortillas on a baking sheet and bake for about 3 minutes per side, until they are crispy.
Remove tortillas from the oven and top with bean mixture, then cheese. Return to the oven for about 5 minutes.
Add topping and enjoy!