I believe Japanese rice is already about 10 grams less in carbohydrates per every 100-gram serving. I'm sure you'll get a lot of quizzical looks from the servers when you say "no rice". As for noodles, Japan has a multitude of types: udon, soba, ramen, somen. Have you looked into their carb content as well?
Many dishes have sauces with sugar (it's a near-staple with soy sauce, mirin, and sake combined).