Sesame-encrusted Tuna

The tuna is supposed to be deep red and firm to the touch, although we don't really feel comfortable asking to poke the fish before we buy it.

The sauce:
1 medium scallion, with the green part sliced into little rings and the white part minced
2 tsp. minced fresh ginger
1/4 cup soy sauce
1/4 cup rice vinegar
1/4 cup water
1-1/2 tsp. sesame oil
2-1/2 tsp. sugar (although this is probably optional. at least use less.)
1/4 tsp. red pepper flakes

The fish:
Dry the tuna really well with paper towls
Coat it with vegetable or light olive oil (about 1 tsp.)
Season both sides of the fish with salt and pepper
Coat with sesame seeds

Heat 1 tbs. oil on high heat until you see little wisps of smoke
Put the fish in, and swirl the pan around to get the oil underneath
Set the timer for 30 seconds, then turn down to medium
Cook 1-1/2 minutes until there is a golden crust on the first side
Flip and cook for roughly 1-1/2 minutes on the second side (depending on thickness) for rare
Up to 3 minutes for medium rare but no more than this is recommended

Slice immediately and spoon the sauce over it. Eat!