Place the peas in a large pot, cover with water and soak overnight. Drain the peas and set aside.
In a large pot, melt the butter over medium-high heat. Add the onions and cook, stirring, for 2 minutes. Add the carrots and scallions. Cook stirring, until just soft, about 3 minutes. Add the garlic and cook, stirring, for 30 seconds.
Add the chicken and cook, stirring, until beginning to brown. Add the drained peas, salt, pepper, and cook, stirring for 2 minutes.
Add the chicken stock, the ground cumin and paprika. Cook stirring occasionally for 30 minutes, add the potatoes and cilantro. Cook for 30 more minutes or until the peas are tender, about 1 hour. (Add more water or chicken stock as needed if the soup becomes too thick.)
Remove the skin and debone it, breaking the meat into bite sized pieces, and return the meat to the soup. Season with salt and pepper and serve.