Here is the full list of all 26 Must Dash Amigos achievements.
Launch the game for the very first time
Win your first gold trophy in Time Trial Mode
Complete a Challenge for the first time in Challenge Mode
Splat an Avocado with the Gwack-a-Mole Mallet
Survive after being turned into an Avocado
Hit 10 enemies with a Flaming Burrito
Hit 10 enemies with a Mega Burrito
Hit 10 enemies with an InvinciBull
Win your first race
Win your first battle
Splat 20 Avocados with the Gwack-a-Mole Mallet
Hit 50 enemies with a Flaming Burrito
Splat 50 Avocados with the Gwack-a-Mole Mallet
Hit 100 enemies with a Flaming Burrito
Use a Speed Boost 1000 Times
Unlock all of the extra outfits for every character
Win every round of a 7-Round race
Score more than 8000 points in a single Battle
Win a Battle without getting killed once
Splat 100 Avocados with the Gwack-a-Mole Mallet
Destroy 50 Piñata Stampedes
Complete every single Challenge
Get a gold trophy for every single Time Trial
Win 150 Races
Win 150 Battles
Complete a Grand Tour Tourney