Quarter, core, and slice the apple into ¼-inch-thick pieces; set aside. Heat the oil in a 12-inch skillet over medium heat. Add the ginger, onion, and garlic and cook, stirring, until the onion is tender and golden, 7 to 8 minutes. Add the curry powder, coriander, cumin, salt, and cayenne and cook, stirring, for 1 to 2 minutes. Add the tomatoes, apple, and 1 cup water and bring to a boil over high heat. Reduce heat to medium and cook about 5 minutes. Add the peas and coconut milk and cook for 5 to 8 minutes. Add the shrimp and cook for 2 to 3 minutes or just until the shrimp are cooked. Stir in the cilantro. Serve with hot cooked rice.