Place a heavy skillet/saucepan on medium heat and add the oil.
When the oil is hot and shimmers, add the chopped onion and cook until soft.
Add the minced garlic and cook until the garlic is soft and fragrant.
Add the salt, chilli flakes and ground cumin and mix until all blended.
Add the tomato sauce, black beans and sweet bell pepper and cook until the peppers soften (5-7 minutes). Stirring frequently. Add the smoked paprika and squeeze on the juice from the lemon at the end of cooking and stir to combine.
Remove from heat and let come to warm temperature.
Lay out the warm tortillas, spoon on the black bean mixture, layer on the avocado slices, sprinkle on the cilantro and drizzle with the Cashew Crema.