If you get sushi-grade tuna you will definitely want to have this rare (it has to be graded to a higher standard so it is okay to eat raw). Regular tuna we normally have medium. Well done tends to make it rather dry.
Can also be cooked under broiler or sautéed in nonstick pan for roughly the same amount of time.
Dried herbs can be used in place of the fresh. Soak them in the lemon juice for 5 – 10 minutes before making sauce.
Keywords: grilled tuna, tarragon sauce