Combine sugar, salt and spices in a container and mix well. You will need approximately ¼ to ⅓ cup of the mixture per fillet. (Store the rest for next time!)
Rinse tuna and pat dry. Cover generously on all sides with the sugar rub. Wrap in plastic wrap and refrigerate for 3 days. At this point, the tuna is cured and ready to eat. Slice and serve within 3-4 days. Alternatively, vacuum seal it and it will last about 10 days. (This vacuum sealer is very affordable and effective.)
Recipe by Between Carpools at https://betweencarpools.com/move-over-beef-jerky-cured-tuna-is-the-new-kid-in-town/