In a large mixing bowl beat feta cheese and butter with an electric mixer on medium speed until combined. Beat in egg and Greek seasoning. Beat in as much of the flour as you can with the mixer. Stir in the remaining flour.
With your hands, knead in the olives and tomatoes. Divide dough in half; shape each portion into a 5-1/2-inch-long log. Wrap in plastic wrap or waxed paper; chill for 4 to 24 hours.
Preheat oven to 375 degree F. Cut each log into 1/4-inch-thick slices. Place 1 inch apart on an ungreased baking sheet. Bake about 15 minutes or until edges begin to brown. Serve warm or at room temperature. Makes about 40 wafers.