Mix your meatball ingredients really well then roll into golfball-size or grape-size balls, these can be frozen. To prepare your soup, boil the water, fish sauce, sesame oil, sambal oelek and garlic for five minutes, then add meatballs and cook at a good simmer for 20 minutes (five minutes more if meatballs are frozen). Now add the spring onion and rest for five minutes to infuse before serving hot.