Wtf I Just Found Out That Furina Can Do This 

Not really, you do have to recast her skill. Which only gives you like 10 or so seconds before she drops in the water.

@@spencerandmainzwithcoffee exactly as long as you recast it infinitely you can walk on water infinitely but kokomi can't recast water walk ability after water walk duration ends

Furina really helps me because she can always walk on water

Even if she is only a human, like a lot of people in Teyvat she has strong elemental powers

Hehe