Prepare the tuna by cutting it lengthwise into three triangles. Season the tuna with salt. In a separate bowl mix together equal amounts of pepper, poppy seeds, and sesame seeds. Then roll each piece of tuna into the seed mixture. Heat a large sauce pan on high heat with peanut oil until hot, then carefully sear each side of the tuna in the oil. Cook through about a 1/4 inch leaving the inside rare and red. Chill the pieces of tuna in the refrigerator.