In a medium bowl, dissolve the sea salt in the water. Add the pumpkin seeds and cayenne pepper. Gently stir the mixture for a few seconds. Place in a warm spot and let sit overnight or for at least 7 hours. Drain the pumpkin seeds in a colander, and spread them out on a large sheet pan. Place in a warm (no more than 150°) oven for 5-6 hours or until the seeds are completely dry and crunchy. Store in an airtight container.