Preheat oven to 400°F. Place oven rack in middle of oven.
In a food processor, coarsely grind sunflower seeds with flour, wheat bran, and caraway seeds if using. With the motor running, add oil and 6 Tbsp. water. Blend just until the mixture forms a ball. Transfer dough to a lightly floured surface and roll out to 1/8-inch thickness. Cut into 1-1/2 inch squares with a knife. Transfer squares to an ungreased baking sheet. Prick each square several times with a fork. Sprinkle crackers with salt and bake on middle rack of preheated oven 10-12 minutes, or until golden.
Transfer crackers to cooling racks and allow to cool.