BOSTON — Islamic communities across Massachusetts are opening their doors to foster better understanding of the faith.Sunday afternoon's second annual "Open Mosque Day" events are being held in more than 20 Islamic houses of worship statewide.Organizers say visitors will be given tours, hear a brief introduction to Islam and observe a Muslim prayer service.Wafaa Wahabi of the American Islamic Center in Everett says the event is intended to help dispel misconceptions about Muslims.