Using your hands, squeeze excess moisture from zucchini and onion. Place in a large bowl. Add corn, flour, egg and half the ricotta, then mix well to combine. Season with pepper.
Spray a large frying pan with oil and heat over medium-low heat. Working in batches, spoon 1/4 cupfuls zucchini mixture into pan. Cook for 4 minutes on each side or until golden and cooked through. Repeat with remaining zucchini mixture to make a total of 6 fritters.
Place 3 fritters in each lunch box with strawberries, pepitas and remaining ricotta.