This potato salad combines earthy, waxy fingerling potatoes with crunchy spring vegetables and mayonnaise flavored with fresh herbs.
Place potatoes in a large pot with enough water to cover by several inches. Bring to a boil over high heat, add 1 tablespoon salt, and lower to a gentle boil. Cook until potatoes are tender when pierced with a knife, about 15 minutes. Drain into a colander. Using gloves or paper towels to protect your hands, slice hot potatoes into 3/4-inch-thick rounds. Drizzle with vinegar, and set aside.
Fill a large bowl with ice and water. Fill a large straight-sided saute pan with water, and place over high heat. Bring to a boil; add 1 teaspoon salt and the asparagus. Cook until just barely tender, about 3 minutes. Transfer to ice bath until cool. Dry, and cut diagonally into 2-inch pieces. Place peas in boiling water, and cook until bright green, about 1 minute. Drain into a colander; transfer to ice bath to stop cooking. Dry on towels.
Place mint, basil, mayonnaise, lemon juice, remaining teaspoon salt, and pepper in the bowl of a food processor, and pulse until smooth. Transfer to a large bowl, add reserved potato mixture, asparagus, peas, sugar snap peas, and fennel, and toss to combine. Garnish with basil and mint leaves, and serve.
Any new potatoes can also be used.