The Winflex prototype shows us that just using an inflated ring doesn’t really work – or that they didn’t know how to make it work. A LEI kite doesn’t have the rigid element so that wouldn’t be a tensairity beam I think. You can’t do this with a LEI kite: Tensairity demonstration bridge
If my understanding is correct you’d need a rigid element to spread the load. So I wouldn’t know how you could use water instead of aluminium say.