Add grated zucchini to a strainer over a small bowl. Sprinkle with 1 tsp salt and mix. Let it sit for 10 minutes to "sweat out" the moisture, then squeeze out all excess liquid using your hands or a cheesecloth.
In a medium bowl, combine the prepared zucchini, egg, purple onion, garlic paste, flour, baking powder, lemon juice, and salt/pepper. Mix well.
Preheat your Blackstone griddle to medium-low heat and add oil of choice (I use grapeseed oil). Using a spoon or ice cream scoop, drop small portions of the zucchini mixture onto the griddle. Sauté until each side is golden, about 4 minutes per side.
Remove the fritters from the griddle and place them on a paper towel-lined plate to absorb any excess grease.
Sprinkle with coarse sea salt, if desired, and serve with a side of tzatziki sauce.
