Heat the oil in pot set over medium-high heat. Add the garlic, ginger and chili flakes and cook 1 minute. Add the stock and soy sauce and bring to a simmer. Add the clams; cover and cook until they just open. Sprinkle with green onions and serve.
Note: Discard any clams that do not close when tapped before cooking, or that do not open after cooking. Both are signs the clam is dead and should not be eaten.