Take some thick stretchy blue fabric and sew them onto a pair of fabric slippers with the top cut off. The fabric on the slippers will give you something to sew onto and the soles won't look huge and thick like boot soles are.
I haven't watched any Naruto lately, but from what I remember, the characters' shoes don't have buckles on them. They just seem kinda "plush" at the toe and around the top, so you can just use a little strip of quilt batting or just fold up some random fabric and stuff it with that to get the same effect.
You'd also probably get more replies if you posted in the anime/manga section since most people know it for the anime/manga rather than the games.
PEACE OUT =)
Amy the Yu
Next Convention: Youmacon
2009 Cons: Katsucon, Con-G, MacTAC, Ad Astra, Anime North, Colossalcon, Polaris, Otakuthon, Otakon, CN Anime, Youmacon, DTAC maybe more...