Place the scallops in a single layer in a resealable plastic bag and freeze for 1 hour. (This makes them firmer and easier to dice.) Cut the frozen scallops into 1/4 -inch pieces.
Rinse the clams under cold water to remove any grit. Shuck the clams: Slide a clam knife between the shells and twist to pry them apart. Detach the clam from the top shell, then slide your knife under the clam to detach it from the bottom shell. Remove any shell fragments from the meat, then coarsely chop. (Clean and reserve 16 half shells for serving.)
Toss the scallops and clams with the lemon juice, olive oil and jalapeno in a medium bowl. Spoon into the reserved clam shells. Sprinkle with salt and serve immediately.
Photograph by Jim Franco
Recipe courtesy Ted Allen for Food Network Magazine