Do you live anywhere near a dive shop or store that caters to scuba diving?  If so, check out what they have in the way of reef-walking booties, as those are lightweight (often made to fit with your feet in the fins so they don't need to be removed) with a very good sole that will prevent being cut from the sharp coral.  You can also do the needed research and then buy them through Amazon, but it's always good to actually see, touch (and maybe try on) footgear before you purchase anything.