I think the fastest way of killing Suqahs, although dangerous, is using a Cannon on them. Cannon the ones in the north eastern part of Lunar Isle. Be careful as some Suqahs on this part can use Mage. Other than cannoning or if you get hit too much by this method, there's always drinking a super set and killing the ones near the Astral RC altar. (This is slower because they are more spread out, but these guys can't use Mage)