Preheat oven to 320F/160C. Line work station with a sheet of parchment paper (the size of your baking tray) and scoop seed mixture onto paper. Top with another sheet of parchment paper and use a rolling pin to roll the mixture into a thin layer (I like my crackers thin. Under 1/4-inch in thickness). Slide parchment paper gently onto a baking tray, then gently peel away the top sheet of paper. (Go slowly to stop the seeds from sticking to it). Sprinkle crackers with more sea salt and bake for 35-45 minutes, or until golden.