In a bowl, mix steamed rice, Katsuobushi, and 1 tsp of the sauce. (save 1 tsp later.) Slice garlic thinly and chop green onion.
Wet hands with water and place 1/2 rice in one hand, and press and form into a triangle shape onigiri. Repeat and make 2 rice balls.
Heat a frying pan with oil and sliced garlic at medium heat. Cook the garlic until crispy, and remove them from the pan. Place the onigiri rice balls in the pan, and cook until browned and crispy on one side for about 3 minutes. Flip and cook the other side as well. Add the soy sauce to the pan, turn off the heat, and coat the onigiri with the sauce.
Serve on a plate and top with the cooked garlic slices and chopped green onions.