Preheat the oven to 300ºF and line a baking tray with parchment paper. In a large bowl, mix all the seeds together. In a small bowl, mix together the remaining ingredients (tamari through water). Pour the wet ingredients into the dry and stir till combine. Allow them to sit for about 20 minutes. This allows the flax and chia seeds to become gelatinous which is how they will stick together.
Pour the mixture onto the lined baking tray and spread using the back of a spoon or an offset spatula till it’s even and about 1/4 inch thick all around. Score lightly with a knife lengthwise and widthwise so that the crackers will be easier to cut or break later.
Place the baking tray in the oven and bake for about 35 to 40 minutes. Turn off the heat and allow crackers to stay in the oven while it cools, for about an hour. Remove from oven and cut or break along the score lines. Store any left-overs in an air-tight container and it will keep for up to a week or so.