This page offers a guide on how to get the second hidden Shine Sprite. You can obtain this Shine in any of the episodes in Gelato Beach.
Spray the Dune Bud Behind the Tower
To get this hidden Shine, you’ll need to head up towards the central tower and find the Dune Bud just behind it. When you spray the Dune Bud, a set of stairs downwards will appear. Quickly spray down the wall in front of the stairs to reveal a sticker of a Shine Sprite. You only have a short amount of time before the stairs are buried by sand again, so you’ll need to be quick. You can try as many times as you like though, since the Dune Bud does spawn in again.
When you’ve revealed the whole Shine sticker, a Shine Sprite will spawn on the top of the hill that overlooks the tower and the beach. Remember, to get there you’ll need to spray the Dune Bud in the alcove to reveal a set of stairs up to the path along the cliff. Alternatively, you can also wall jump up the alcove to reach the path.