In a small bowl combine butter, oil, oregano, rosemary, garlic, paprika, 1/2 teaspoon salt, and cracked black pepper. Cut ciabatta loaf in half horizontally; cut each half crosswise into thirds to make 6 pieces. Very lightly brush cut sides of bread with some of the herb mixture. Set remaining herb mixture aside.
Score flank steak on both sides, making shallow cuts at 1-inch intervals diagonally across steak in a diamond pattern. Heat a very large skillet over medium-high heat until very hot. Sprinkle both sides of steak with additional salt and pepper. Cook steak in hot skillet, uncovered, for 12 to 15 minutes or until medium-rare (145 degrees F), turning once halfway through cooking. Transfer steak to a plate. Cover; let stand for 5 minutes.
Meanwhile, place half of the bread, cut sides down, in the skillet; cook about 1 minute or until toasted. Remove from skillet. Repeat with remaining bread.
Add remaining herb mixture to skillet. When mixture begins to bubble, add tomatoes. Cook and stir for 4 to 6 minutes or until skins split. Remove from heat; let stand for 5 minutes.
Meanwhile, thinly slice steak across the grain. Arrange thinly sliced steak on toasted bread; top with tomatoes. Serve immediately.