Saute onions, ginger, garlic and salt in large pot for 10 minutes. Add broth and bring to a boil.
Add sweet potatoes and cook on medium-low heat until sweet potatoes are tender (about 20 minutes).
In a medium-sized, heat-safe mixing bowl, combine the peanut butter and tomato paste, then transfer 1 to 2 cups of the hot broth to the bowl. Whisk the mixture together until smooth, then pour the peanut mixture back into the soup and mix well. Stir in chickpeas and collard greens.
Simmer for about 15 minutes on medium-low heat, stirring often.
Optional: add hot sauce to taste and serve over cooked brown rice.
Garnish with a sprinkle of chopped peanuts.