Heat the oil in a large pot or Dutch oven over medium heat.
Add the diced onion and cook for 3 to 5 minutes, or until it becomes translucent.
Add the minced garlic and chilies to the pot and cook for another minute until fragrant.
Stir in the black beans, yams, water, currants, toasted cumin, coriander, cinnamon, and salt. Increase the heat and bring the mixture to a boil.
Once boiling, reduce the heat to low, cover the pot, and let it simmer for 20 to 30 minutes. The stew is ready when the yams are tender and can be easily pierced with a fork.
Remove from heat and stir in the fresh cilantro (or parsley) and lemon juice just before serving.