I don't think the roulettes are open for lunch. We had Chinese food at a roulete and they had steak, burgers, crepes, Italian, each roulette specialized in something different. Meals there were under $10 each.
You can also get sandwiches near the market in Papeete at least at lunch. We got 12" crab torpedos (hoagies?) for about $4 each. Lunch meat and cheese sandwiches were about $2 to $2.50 each.