Cut fillets into pieces about 4"x1 1/2". Stuff with mixture of ginger, salt, ham and spinach. Roll and fasten with toothpicks. Make batter by combining flour, egg and water. Stir in sesame seeds. Dip fish rolls into batter and deep fry until rolls are golden brown, about 4-5 minutes, or until fish is done. Remove toothpicks before serving with your choice of dipping sauces.