Preheat oven to 450ºF.Prepare Filling. Heat 1 ½ Tbsp. olive oil in a large skillet over medium heat. Add onion; cook until soft, about 6 to 8 minutes. Add garlic, tomato paste, chipotle peppers, chili powder, cumin, and cinnamon; cook until aromatic, about 2 minutes.Add can of black beans (including bean liquid) and pumpkin puree; stir well to combine. Season mixture with kosher salt and let simmer until thickened, about 5 minutes. Taste and adjust seasonings as needed.

Warm Tortillas. Wrap the corn tortillas in a damp paper towel. Microwave 30 seconds to steam the tortillas, making them pliable enough for taco assembly.

Assemble Tacos. Drizzle remaining 1 ½ Tbsp. olive oil on a large rimmed baking sheet. Arrange corn tortillas on baking sheet, rubbing in oil to lightly coat.Spread the black been pumpkin mixture over half of each tortilla (I use a heaping ¼ cup filling for each taco), then sprinkle with cheese. Fold the tortillas, creating a taco around the filling. (I like to carefully flip the tacos at this point, so the cheese side is facing down.)

Bake Tacos. Place baking sheet in the oven and bake tacos until crispy, about 12 to 15 minutes. Remove from the oven and allow to cool 2 to 3 minutes – the tacos will get even crispier as they cool.Mix sour cream or Greek yogurt with lime juice in a small bowl. Add dollops on top of tacos, and garnish with additional toppings of choice.