Mix all the ingredients together in a large bowl and add the warm water. Stir well and let sit for an hour, stirring every 15 minutes.
Line 2 baking sheets with parchment paper or silicone mats. Divide the seed mixture between the two pans and pat or roll the seeds out into a thin even layer. You won't fill the entire pans, but get it nice and thin.
Bake for an hour, or until firm and crisp. Let cool on the pans and then break into pieces.
Store in an airtight container at room temperature.
Notes
You definitely don't need to use as big a variety of seeds as I have here, but you'll want to have a good mix of sizes, because if you use only large ones like pumpkin and sunflower the crackers won't hold together. There are lots of varieties, so mix and match.