Tons of other people have come to think that their method is +EV , but its impossible to have one unless there is an exploit. If there existed any such method all the casinos would have shut down by now.
But since you say a particular dice site, do you mean by an exploit ? As the factors which would make you think that would be max bet size and lowest bet possible on the site or a zero or negative house edge. There is no other different way to beat the house.