I find I am OK if I avoid the rice (white or brown makes no difference) and starchy stuff. Unfortunately that means avoiding a large proportion of typical menus. It also means a more expensive meal, because the protein items are invariably more expensive - think sashimi versus sushi for example.
Yes, the dressings are made with sugar, the food is seasoned with sugar and even the tamago omelette is made with a little sugar but as I am T1 and have to bolus for protein anyway, I don't worry too much about the carbs in these as long as I don't go overboard.
One tip is to order two appetizer/salad type dishes as mains will always come with rice. I've managed to get assorted fishy things over salad, then there is also yakitori, or grilled skewers of meat and other tasty things. And tofu stuff is usually pretty low-carb too. I especially love the grated daikon radish that comes with the salads. It's crunchy and refreshing and low in carbs.
For more ideas I can recommend the Just Bento website. It's a fantastic resource for Japanese food and recipes and the blogger herself has blood sugar issues so understands the challenges involved.