It's certainly not strange at all, and if you pick up any random novel and flip through it you'll see that dialog without attribution is used all the time.
The question as to whether it's confusing, however, is entirely situational.
It can be, particularly if you've have a lot of back and forth dialog without attribution. I've read novels where I've had to go back a paragraph or two in order to figure out who was saying something, which is never good.
However, in your example, "Hey, Daichi." Kiyoshi tapped me on my shoulder. while you've attributed the dialog through a clear linking action, I think you've gotten the order of events backwards in order to do so.
I don't think Kiyoshi would first speak to you and then tap you on the shoulder. I believe people tend to tap someone to get their attention and then talk, not tap after they've gotten your attention.
I believe there's a term for this, but it has escaped me. Regardless, make sure your linking actions make sense and are useful to the reader whether to orient them in space, help them better visualize what's going on, or to illustrate the mental state of a character.
When they are used simply as a he said/she said replacement they can interrupt the flow of a scene and your reader's connection to the story.