Here is the full list of all 26 Must Dash Amigos achievements worth 1,000 gamerscore.
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