Adjust two oven racks to upper-middle and lower-middle positions, respectively. Preheat oven to 450ºF. Line two large baking sheets with parchment paper.
On a large paper towel-lined plate, place sliced zucchini in an even layer and lightly pat dry.
Into a shallow bowl, add breadcrumbs, Parmesan, olive oil, salt, garlic powder, and onion powder. Whisk together until dry ingredients are coated evenly in oil.
In another shallow bowl, add egg whites and lightly beat until frothy. In a separate shallow bowl, add flour.
Start by dredging zucchini sticks into flour, lightly tap to remove excess, then dredge into egg whites, letting any extra drip back into the bowl, then place into the panko mixture. Rotate and lightly press panko onto the zucchini, aiming for an even layer on all sides. Divide zucchini fries on the 2 prepared baking sheets, leaving about ½"space in between the fries.
Bake for 12 minutes, then gently flip zucchini using tongs. Place baking sheets back in the oven, but rotate positions so that the top baking sheet is now on the bottom and vice versa. Bake for another 12-14 minutes, until fries are crisp and golden brown. Serve immediately.