Which ingredient is NOT included in the Raw Ahi Tuna dish?

The Raw Ahi Tuna dish is characterized by its fresh and vibrant ingredients that complement the tuna's flavors. Among these, cilantro, mango segments, and green onion are traditional components that enhance the dish's taste and presentation.

Mango segments, for example, add a sweet and tropical note that balances the savory and rich profile of the tuna, while cilantro contributes a fresh, herbaceous element that brightens the overall flavor. Green onion introduces a mild onion flavor and a bit of crunch, which also adds to the freshness of the dish. On the other hand, roma tomatoes are not typically associated with this particular dish and may not provide the intended flavor dynamics.

By understanding the combination of ingredients typically used in the Raw Ahi Tuna dish, it's clear that mango segments do not belong to this list, thus making it the correct answer to the question about which ingredient is not included.