Tuna tartare is a seafood dish made from raw, fresh tuna that has been finely chopped or diced. The tuna is typically marinated with various seasonings including soy sauce, sesame oil, and ginger. It's often served on a bed of avocado or with a side of crackers or toast points. This appetizer is a staple in many sushi and European restaurants because of its delicate yet savory flavors.