Heat the olive oil in a large saucepan. Add the garlic, onion, lemon zest and curry powder and cook over moderate heat, stirring occasionally, for 5 minutes. Add the andouille and cook over moderately high heat for 2 minutes. Add the stock and bring to a boil. Add the clams, cover and cook, shaking the pan a few times, until they open, 5 minutes.
Using a slotted spoon, spoon the clams into shallow bowls. Stir the cilantro into the broth, then pour over the clams. Serve with lemon wedges.