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 (updates with addresses will be coming soon, this is a rough list):
坦々亭 Tantantei: Chinese restaurant in Ginowan.
ラーメン工場無双 Ramen Factory Musou: Ginowan
あけぼの Akebono: Naha
風風ラーメン Fuu fuu ramen: Awase
*Arashi ramen, Stripe ramen, and Tenkaipin ramen are very popular with Americans, probably 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. 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.