No you probably won't be able to find Middle Eastern or Arab groceries in Beijing. They only open grocery stores that would appeal to the entire community not just a select few. Also, if there are any but I doubt it it would probably be a small local owned one. Chances are slim to none. You definitely won't find a big Arab grocery store in Beijing. I've never seen one nor heard of one. 

I would imagine that there would be some, we had them in Guilin which is a very small city in the interior of China.
One good bet is to check near mosques, as they often include products from the Middle East in addition to food that is prepared in accordance to Muslim traditions.