Soak the peas in cold water overnight. Drain, add them to a pot, cover with water, place over medium-high heat, and let simmer until tender, about 40 minutes. Reserve ¼ cup of the cooking liquid and drain. Add all but ¼ cup of the cooked peas to a food processor. Add the oil, vinegar, garlic, ginger, thyme, onion powder, paprika, and 1 tablespoon of the reserved cooking water and puree until smooth. Add additional cooking water as necessary to thin to the desired consistency. Season with kosher salt. Transfer the dip to a bowl and gently stir in the remaining ¼ cup black-eyed peas.