"A fulano de tal" it´s a expression that means somebody... it´s like when you say: X person. Fulano = name de tal = lastname

Fulano, mengano, zutano y perengano are four generic people used in spanish when you want to speak of people and their identities are not important. For example: "Un fulano te trajo esta carta", is like "Some guy brought you this letter.", is not important who did. You can use one, two, all, depends on the phrase. Saludos