You can peel them by soaking them in water for a couple days (make sure you change the water daily). This skin comes right off, but you have to be a little patient! I don’t think it’s necessary to blanche them so long, I’ve read only a few seconds is enough, but can’t vouch for it.
Starjen42 has it right. The presence of prussic acid may be the fundimental definition of bitter almond varieties. There are not many bitter almond trees and they are mostly if not entirely grown outside the US. The bitter almond looks more like a spanish almond – it’s noticably broader and shorter that the USA sweet varieties.
I think your right about heating to make bitter almonds safer, but I think the Prussic may be more in the meat then the skin. On my website, www.almondsalive.com there is a nutritional analysis of whole and blanched sweet almonds – the nutritional value of the skin (and a small amout of meat tags) is the difference between the two columns. Most acids (except B6) are in the nut meat. Also, for bitter almonds more than heat is needed – a cyanide removal process of some sort.
Our sweet almonds are not only safe but in there raw form, right from the tree are as close to a perfect human food as there is. It is probably better to not process almonds in hot water. The almond skin protects the seed and maybe thats why most of the beneficial antioxidents are in the skin. Almonds held in hot water would still be nutrious food but the water will extract some of the antioxidents and may extract or modify elements and micronutrient constituents that are not currently understood or measured in a nurtitinal analysis. .