Ahi Tuna Steak (sushi grade tuna - organic?)

First shot at cooking tuna I took tips from friends on the forum and some ingredients from the internet and created a marinade that seemed to work just fine.  The key is to buy high end product and to not overcook the tuna, period, end of discussion.

Ingredients for Marinade  

1/4 c. olive oil
2 tbsp. lime juice
1 tbsp. dry mustard
2 tbsp. dried cilantro
1 tbsp. chili powder
1 tsp. black pepper
1 tbsp. mustard seeds
4 to 6 tuna steaks

Mix ingredients and brush onto tuna steak. Refrigerate for several hours.  For ¾” steaks, sear on each side for 1 minute and remove from grill.   You have a few options on how you want to present thicker steaks and cooking them until they flake (like many websites tout) will result in dry tuna; period.