Heat a wok or 12-inch skillet over medium-high heat. Add oil and rotate wok or skillet to coat the sides.
Add black-eyed peas, onion, corn, rice, thyme, garlic salt, and cayenne; stir-fry until heated through, 3 to 4 minutes. Add spinach and stir-fry until it begins to wilt, 1 to 2 minutes.