In a heavy soup pot combine rice and water. Bring to a boil, reduce to low heat and cover. Cook until dry, about 12 to 15 minutes. Stir in sesame oil, scallions, salt and pepper. Reserve warm.
Mix together sesame seeds, coriander, salt and black pepper. Coat all sides of tuna in seed mixture. Heat peanut oil in cast iron skillet over high heat. Sear tuna on all sides leaving center rare. Reserve warm.
For Wasabi Cream
Heat cream to a scald. Add wasabi and wisk well to incorporate. Bring to a simmer and reduce until cream coats the back of a spoon. Transfer to a squirt bottle and reserve warm.
For Fried Wontons
Cut wonton skins to 1/16" wide strips. Toss strips in cornstarch to separate. Shake off any excess cornstarch. Heat peanut oil to 350º to 375º. Slowly drop wonton strips in hot oil. Cook until crisp and lightly browned. Drain on paper towels.
Squirt a zig-zag of wasabi cream on plate. Place one timbale of rice in center of plate. Slice five 1/2" pieces of tuna per plate and arrange around rice. Garnish plate with diced bell pepper and pickled ginger. Place handful of fried wontons on top of rice.