Set desired amount of peas out from freezer.
Cook macaroni as directed (I try and buy the ones with the ridges).
Grate carrots and onion.
Chop the green onion.
Mix together the mayo, milk, mirin, vinegar, salt and pepper.
Transfer mac to a large bowl, cover in liquid mixture (start with only 3/4th of the mix) while evenly distributing the carrots, onions and peas. Mix well.
Add in the rest of the ingredients per taste, set some green onion aside for garnish at end.
Transfer to serving bowl and finish with green onion.