Begin by finely mincing the green onions and parsley, using a small food processor for efficiency. Once minced, incorporate the paprika, salt, pepper, and Cajun seasoning, pulsing briefly to blend. If a food processor is unavailable, finely chop the green onions and parsley by hand with a sharp knife.
In a large bowl, combine the herb mixture with the ground chicken, breadcrumbs, egg, minced garlic, and milk. Use your hands to thoroughly mix the ingredients until well incorporated.
Form the mixture into approximately 20 meatballs, each about 2 inches in diameter. For uniformity, a cookie scoop can be used. Place the formed meatballs on a clean plate and cover them. Chill in the refrigerator for at least 30 minutes to firm up.
Heat the olive oil in a large skillet over medium heat. Cook the meatballs in batches of 10-12, turning them to ensure they brown evenly on all sides, about 1-2 minutes per side. Continue cooking until the meatballs reach an internal temperature of 165°F (measured with a digital meat thermometer). Once done, transfer the cooked meatballs to a clean plate.
In the same skillet, melt the butter, then add the buffalo sauce. Whisk the mixture until it begins to simmer and bubble gently.
Return the cooked meatballs to the skillet, gently stirring to coat them in the buffalo sauce. Allow the meatballs to soak up the sauce and reheat for about 3-5 minutes.
Serve the meatballs with a side of carrots and celery, and top with blue cheese or ranch dressing, fresh green onions, and blue cheese crumbles, if desired.