In a large soup pot, sauté onion and garlic over medium heat in oil until onions become translucent.
Add spices (including dried or fresh oregano).
Add yams and continue cooking for a couple minutes, stirring occasionally.
Season with a few good pinches of salt.
Add cooked beans and water to just more than cover the vegetables.
Simmer until the yams are tender but not falling apart.
Take the soup off the heat and blend with hand blender (or blend half of the soup in a blender and add back to the pot). Add more water to desired consistency.
Stir in the greens until wilted (cook for up to 2 minutes if using tougher greens like kale).
Finish the soup by seasoning with lime juice and salt to taste.