Preheat the oven to 400 degrees F (200 degrees C). Place a rimmed baking sheet in the oven to heat up.

Place zucchini in a bowl. Add oil, salt, pepper, garlic powder, and cayenne; toss to coat.

Carefully remove the hot baking sheet and spray lightly with cooking spray. Spread out zucchini in an even layer without overcrowding.

Roast in the preheated oven until golden brown and crisped, turning halfway, about 20 minutes. Squeeze lemon juice on top and garnish with parsley. Sprinkle sea salt on top to taste.