As the others have mentioned, you can access the Practice Arena again after you complete it the first time. It should be near the News tab and Battle Pass area.
As for moving targets, I have passed the idea along to the team. I've seen some players use Shockwave to knock NPCs up into the air to practice aim training.
As for moving targets, I have passed the idea along to the team. I've seen some players use Shockwave to knock NPCs up into the air to practice aim training.