Lay your cold fish on a cutting board and with a sharp knife, slice it against the grain. This means that you want you knife to be perpendicular, not parallel, to the white muscle fibers that run through the fish. If a piece is really long, cut it into smaller pieces. You want bite size pieces.
Arrange your fish on a platter. Squeeze lime juice over the top. Start with 1/2 a lime. The juice will turn the fish slices slightly white. You want enough lime to lightly dust all of your fish slices without drowning them.
Sprinkle the fish with the olive oil. Then, scatter with the chives and finish with sea salt, pepper and black sesame seeds. If you have Mom's Special Salt, use this instead. Serve.