Step 1: Finely chop the preserved lemons, discarding any seeds or mushy pulp. (Scrape out the latter with the side of your knife.) You need about 1/2 cup. Place it in a bowl with the jalapenos and olive oil. Stir to mix. The recipe can be prepared up to 4 hours ahead to this stage and stored in the refrigerator.
Step 2: Set up your grill for direct grilling and preheat to high.
Step 3: Shuck the clams, taking care not to spill the juices. Arrange the clams on the shellfish rack and add a spoonful of preserved lemon vinaigrette mixture to each.
Step 4: Toss the wood chips on the coals or place in your gas grill’s smoker box.
Step 5: Place the rack with clams on the grill. Cover the grill and cook for 1 minute. (This holds in the smoke.) Open the grill and continue grilling until the clam juices bubble and the bivalves are just cooked, 2 minutes.
Step 6: Transfer the clams to a platter or plates. Sprinkle with chives and serve at once.