Lightly spoon flour into a dry measuring cup, and level with a knife. Combine flour and next 5 ingredients (flour through red pepper) in a large bowl, stirring with a whisk. Cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Add cheese, water, and vinegar; stir until mixture just comes together. Divide dough into 4 equal portions, shaping each into a ball. Wrap each ball in plastic wrap; cover and freeze 30 minutes.
Preheat oven to 375°.
Roll 1 ball into an 8-inch circle on parchment paper on a lightly floured surface (dough will be very thin). Sprinkle dough with 1/2 teaspoon seeds, and lightly press the seeds into dough. Cut dough into 8 wedges (do not separate wedges). Place dough on a large baking sheet. Repeat procedure with remaining dough and seeds, arranging on 2 baking sheets. Bake at 375° for 10 minutes or until crackers are brown and crispy. Cool completely on a wire rack. Separate into wedges.