Preheat oven to 375°F.
Mix your dry ingredients: Flour, salt, sugar, both sesame seeds, chia seeds, and pumpkin seeds to a large bowl. Mix until your ingredients are evenly distributed.
Add your water and 1/3 cup oil and mix until a shaggy dough forms. Pour out on the counter and knead any loose pieces of dry flour and dough until it all comes together, 5 minutes. Let your dough rest for 30 in a bowl covered in plastic or a kitchen towel.
Once your dough has rested, cut your dough into 2 to 4 pieces to make it more manageable to roll out. Cover pieces you aren't working with the plastic to keep them from drying out. With a rolling pin, roll out dough to be as thin as your pumpkin seeds.
With a cookie cutter or anything sharp, cut your crackers into snackable sized pieces. Transfer to a parchment lined baking sheet while you continue to cut out dough. If you aren't using a cookie cutter, make sure to try to get the crackers around the same size for even baking.
With your crackers on the baking sheet. Spray with cooking spray or brush with additional oil. Place in the oven and bake 12-14 minutes, rotating half way through. You will know these are done when they develop color around the edges of the crackers.
Wait for crackers to cool and enjoy! Eat them on their own or serve them up with dips, snacks, etc.