Grate potatoes and squeeze out excess water thoroughly.
Mix grated potato with eggs, flour, parsley, salt, and chili flakes.
Brush tray with oil, spread mixture into thin rectangle, and bake until golden and set.
Sauté garlic in oil, add chicken, and cook until browned.
Stir in ketchup, diced green pepper, and soy sauce; cook until coated.
Spread chicken mixture and mozzarella over the potato sheet.
Roll into a log, top with pizza sauce, more cheese, olives, oregano, and chili flakes.
Bake until cheese is melted and bubbly.
Rest briefly, slice, and serve hot.
Tip: Squeeze potato water well so the base holds together when rolled.