Dehydrate the Zucchini: Using the large holes of a box grater, grate the zucchini. Place in a large mesh strainer set over a bowl for 20 minutes to release moisture. Transfer to cheesecloth or a clean towel and squeeze very firmly until dry. You should have about 3 cups of compressed zucchini.
Assemble the Aromatic Base: In a large mixing bowl, combine the dehydrated zucchini, dill, mint, green onions, garlic, and lemon zest. Mix to evenly distribute.
Combine the Binders: In a separate bowl, whisk together the whole wheat pastry flour, oat flour, whole wheat panko, nutritional yeast, sodium-free baking powder, and black pepper.
Unify the Fritter Matrix: Add the dry mixture to the zucchini-herb base and mix just to combine. Add the lightly beaten eggs and crumbled feta; fold with a spatula until a thick, cohesive batter forms. Do not overmix.
Form and Prepare the Medallions: Preheat oven to 425°F (220°C). Line two large baking sheets with parchment. Using a heaping tablespoon, portion 24 even mounds, leaving space between them. Gently flatten each to about 2 inches in diameter and ½ inch thick. Drizzle the olive oil evenly over all medallions.
Bake to a Golden Crisp: Bake 12–15 minutes until the bottoms are golden and set; rotate the baking sheets front-to-back and switch oven racks halfway. Carefully flip each medallion and bake 10–12 minutes more, until the second side is golden, edges are crisp, and centers are no longer moist (optional check: internal temp ≥160°F/71°C).
Serve: Let cool on the sheets for a few minutes. Serve warm with non-fat Greek yogurt and lemon wedges.