Arrange tomato slices in a single layer on several layers of paper towels; sprinkle with 1/2 teaspoon salt. Let stand 20 minutes; blot dry with paper towels.
Preheat oven to 400°.
Place corn, juice, and sour cream in a food processor or blender; process until smooth. Combine 1 1/2 cups flour, 1/4 cup cornmeal, and 1/2 teaspoon salt in a large bowl; stir with a whisk. Cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Add corn mixture; stir until a soft dough forms. Knead gently 3 or 4 times.
Slightly overlap 2 (16-inch) sheets of plastic wrap on a slightly damp surface. Place dough on plastic wrap; press into a 6-inch circle. Cover with 2 additional (16-inch) sheets of overlapping plastic wrap. Roll dough, still covered, into a 14-inch circle; place on a large baking sheet in freezer 10 minutes or until plastic wrap can be easily removed. Line baking sheet with parchment paper; sprinkle paper with 1 tablespoon cornmeal. Remove 2 sheets of plastic wrap from dough. Place dough, plastic wrap side up, on baking sheet. Remove top sheets of plastic wrap.
Combine 1/4 cup basil, cheese, and oregano. Combine 2 tablespoons flour and 1/2 teaspoon salt. Arrange cheese mixture on dough, leaving a 1 1/2-inch border. Using a sifter or sieve, sift 1 tablespoon flour mixture over cheese mixture. Arrange half of tomatoes over cheese mixture. Sift remaining flour mixture over tomatoes; top with remaining tomatoes. Fold edges of dough toward center; press to seal (dough will only partially cover tomatoes). Bake at 400° for 35 minutes or until crust is brown; let stand 10 minutes. Sprinkle with 1/4 cup basil and pepper.