Preheat oven to 375 degrees F. Line a shallow baking pan with foil; lightly coat with cooking spray.
Cook ramen according to package directions, reserving seasoning packet; drain. Stir in butter, half of the seasoning packet, and 2 teaspoons of the chili paste (discard remaining seasoning or save for another use).
Meanwhile, in a bowl combine beef, rice crackers, the egg, green onions, ginger, and 2 tablespoons of the hoisin sauce. Transfer meat mixture to a large resealable plastic bag; do not seal bag. Pat mixture into a 10x8-inch rectangle. Cut off the top side of bag. Place ramen mixture lengthwise down the center of the rectangle. Using the bag, roll sides of meat up and over the noodle filling to make a 10-inch-long roll. Transfer roll, seam side down, to the prepared baking pan. Bake 20 minutes.
Meanwhile, in a small saucepan combine the remaining 1/4 cup hoisin sauce, remaining 2 teaspoons chili paste, and the rice vinegar. Cook and stir over medium heat until bubbly. Spoon warm sauce over meatloaf. Bake about 10 minutes more or until done in the thickest portion (160 degrees F). If desired, top meatloaf with toasted sesame seeds and additional sliced green onions.