You take your fingers and slam a lid on the table. You make this big noise to confront the person in front of you.
You are trying to confront Emperor こういち. You're confronting him about all the kanji he's forcing you, and everyone else, to learn. "Look here こういち! I know you said I'd learn like 2000 kanji in no time, but this is way too efficient! What will the people do when they're done? Do you think they will sit idly by?"