Place the pigeon peas in a medium bowl with 2 teaspoons of salt. Rub the peas gently with the salt for a few seconds, then rinse with cold water and drain well.
Add the pigeon peas and 6 ½ cups of water to a large saucepan over medium-high heat. Bring to a boil and cook for about 45 minutes, or until the pigeon peas are tender.
Drain the pigeon peas, reserving about 1 cup of the cooking liquid in the saucepan.
While the pigeon peas cook, mash the garlic, ají gustoso peppers, remaining ½ teaspoon salt, and oregano in a pilón or mortar and pestle until a coarse paste forms.
Return the pigeon peas to the saucepan with the reserved liquid. Stir in the remaining 2 cups of water, garlic paste, squash, culantro, cilantro, cubanelle pepper, onion, bouillon tablet, bitter orange juice, black pepper, and coconut milk.
Bring to a gentle simmer over medium heat and cook for about 25 minutes, or until the squash is tender and the broth has slightly thickened.
Remove and discard the culantro, cilantro stems, cubanelle pepper, and onion.
Transfer half of the cooked squash and about ½ cup of the cooking liquid to a blender. Blend until smooth.
Pour the blended squash mixture back into the saucepan and stir well to create a creamier texture.
Simmer for 2 to 3 more minutes, then remove from the heat.
Serve warm with white rice, stewed chicken, codfish, or your favorite Dominican main dish.