Here is the full list of all 15 Tanuki Sunset achievements.
Reach the end of Sunrise Beach
Reach the final ramp at the end of the Legendary Trail
High-five Steven the Seagull for the first time
Reach the end of Midnight City
Rescue little Kit for the first time
Reach the end of Sunset Peaks
Clear all the trials at the Arcade
Pet Dio, the dog in Bob's Skate Shop
High Five Steven in all the areas and acquire all the Seagull Stickers
Finish all the story levels fast enough to acquire all the Time Stickers
Get a score high enough on all story levels to acquire all the Score Trophy Stickers
Clear all the story levels without restarting to collect all the No-Death Stickers
Purchase the Imperial Crown and take it from Dio
Purchase everything
Finish first on all trials, Acquire all stickers for every story level