In a food processor, pulse the cilantro with the scallions, garlic, thyme, ginger, chile, allspice and nutmeg until coarsely pureed.
Blend in the olive oil, tomato paste and vinegar. Season with salt and pepper.
Transfer 6 tablespoons of the puree to a large bowl. Add the mussels, cockles/clams and tomatoes and toss to coat.
Tear off four 20-inch-long sheets of extra-heavy-duty foil.
Mound half of the seafood in the center of each of 2 foil sheets. Add the shrimp in a layer on the seafood. Cover with 2 remaining sheets of foil; fold up the edges all around to seal.
Grill the hobo packs over a hot fire for about 6 minutes, or until sizzling and puffed. Using oven mitts, transfer the packs to a large rimmed platter. Open the packs carefully, pour the eseafood into shallow bowls.