Heat a gas grill to high.
Toss the shishitos with the olive oil and salt in a large mixing bowl. Arrange the chiles in an even layer on the grill and cook, uncovered, for 3 minutes. Flip and grill for another 2 to 3 minutes, until the skins are slightly blistered.
Move the shishitos back to the mixing bowl and toss with the soy sauce. Then, quickly place on a platter and top with the katsuobushi flakes.
To consume, simply grab one by the stem and eat the entire pod, seeds and all.