担々麺 (tantanmen) or 坦々ラーメン (tantan ramen) is a popular “Chinese-style” noodle dish in Japan. It is typically seen as ramen (but occasionally as tsukemen, aka dipping noodles). It is often found at ramen and Chinese restaurants. A few shops in Okinawa will advertise it as a specialty dish of the shop. I know of quite a few shops with tantanmen not far from my area. I frequently see banners outside of ramen shops advertising tantanmen.
Tantanmen usually has a spicy broth with thick sesame taste, topped with minced pork and green onions. It is supposedly Sichuan-style, although Japan often tones down the spicy levels and focuses more on the rich, sesame qualities of the broth.
Some of the better places in Okinawa to try tantanmen (I will try to add some more restaurants):
坦々亭 Tantantei, Ginowan: https://goo.gl/maps/krvCHNVhthE2
ラーメン工場無双 Ramen Factory Musou, Ginowan: https://goo.gl/maps/ab42CAQ7peR2
あけぼのラーメン Akebono Ramen, Naha: https://goo.gl/maps/8u1aZTAQHTw
燕郷房 YanKyouFan, Naha: https://goo.gl/maps/548MMuMrwAu
*Arashi ramen 嵐, Stripe ramen, and Tenkaipin ramen 天下一品 are very popular with Americans, most likely due to the fact they have English menus and are close to American bases. I do not tend to patronize these places, but many other people seem to enjoy them, so decide for yourself if you want to check them out. My husband says the fried rice at Arashi is pretty good. Both Arashi and Tenkaipin are large restaurant chains from the mainland. I am not sure on the menus, but I am fairly certain they have tantanmen, or some variation.