Maki Sushi Fillings: Crab: Meat from Dungeness, blue or king crabs is best. Pick over the meat for bits of shell. Tuna: If a piece of tuna is sinewy, simply scrape the meat off the sinews with a sharp knife. Salmon: Slice salmon across the grain into strips about 4 inches long and 1/4 inch thick. Cucumber: Seed a cucumber, then slice it—including some of the skin—into a thin julienne. Avocado: Cut a ripe Hass avocado in half. Carefully strike the pit with the blade of a heavy chef's knife, then twist the knife to remove the pit. Peel the halves, then cut them into 1/4-inch-thick slices.