JERUSALEM — Growing up in the West Bank, Mujahid Sarsur knew next to nothing about the Holocaust and saw little ground to sympathize with a people he saw as his occupier. But thanks to an Israeli roommate overseas, the 21-year-old Palestinian student learned about the Nazi murder of 6 million Jews during World War II and discovered a new understanding of his Israeli neighbors.Now he wants other Arabs to do the same. Sarsur heads one of a handful of Palestinian grass-roots groups seeking knowledge about the Holocaust.On Wednesday, he led a delegation of 22 students to Israel’s official Holocaust memorial, Yad Vashem. The students, fasting for Ramadan, listened closely to their Arabic-speaking guide’s explanations, and were left wide-eyed by the gruesome images of the death camps.