In a small mixing bowl, vigorously whisk the almond butter, water, vanilla extract, and cinnamon until the mixture is smooth and emulsified.
Add the hemp hearts, pumpkin seeds, chia seeds, flaxseed meal, and sea salt to the bowl.
Stir the ingredients together using a sturdy spatula until a thick, uniform dough forms and all seeds are evenly coated.
Line a small rectangular glass container with a piece of parchment paper, leaving some overhang on the sides for easy removal.
Transfer the seed mixture into the container and press down firmly with the back of a spoon to create a dense, flat layer.
Place the container in the freezer for at least 30 minutes to allow the healthy fats to solidify and the bar to set.
Lift the parchment paper to remove the block from the container and slice into a single large, protein-dense bar.