Place the first 6 ingredients in a food processor; add 1/2 teaspoon salt. Pulse until mixture is finely chopped., In a bowl, combine tomatoes and corn; stir in 1 tablespoon herb mixture and remaining salt., Place each fillet on a piece of heavy-duty foil (about 12 in. square). Top with herb mixture; spoon tomato mixture alongside fish. Fold foil around fish and vegetables, sealing tightly., Grill, covered, over medium-high heat until the fish just begins to flake easily with a fork, 6-8 minutes. Open foil carefully to allow steam to escape.