In boiling water, cook potatoes for about 20 minutes until soft. Remove potatoes and run under cold water until cooled. Boil Asparagus and snap peas for 3 minutes. Blanch in ice water to immediately stop cooking (ensuring wonderful texture). Whisk vinaigrette ingredients together. Cut cooled potatoes, asparagus, radishes and green onions. Evenly coat with vinaigrette adding salt and pepper to taste.