Have you seen his entry in the Veterans Affairs site, Jim?
http://www.vac-acc.gc.ca/general/sub...sualty=2059548
Note that if you have a photo of the young man or of his grave, you can upload it to the site, and they will include it. I have done this for a few of our other Fallen.
You should be aware that during the hectic, tumultuous fighting in Normandy, the dead were most often left where they fell, as their buddies had too much on their hands to worry about them. Sometime later, as the immediate area became secure, follow-up units, and sometimes Regimental Padres on their own, would bury the dead where they lay and make a record of their identities and locations. It was usually much later that graves registration units would comb the countryside, exhume these bodies and bury them in permanent locations such as Beny-sur Mer, with all appropriate military honours of course.
If actually engaged in an attack, Rfn Long was most likely killed by mortar or machinegun fire. If during a move, it was most likely artillery. If you know his platoon or company, the War Diaries will you how those casualties came to be (daily entries); if you don't, you'll have to dig deeper, into the nominal roles for the Regiment back in England (unless he was a reinforcement after the actual Normandy landing).
Let us know what we can do to help.