The experience of plucking the first fresh peas from the vine and eating them raw, straight from the pod, is one of those natural highs that gardeners live for. A meal of freshly dug new potatoes is another. This simple recipe combines the two: steam new potatoes in their skins until just tender. Leaving the skins on, slice about 1/2 inch thick. While the potatoes are still warm, toss them with a dressing of one part tarragon vinegar and four parts extra-virgin olive oil and a touch of Dijon mustard. Stir in the raw peas and a little finely chopped onion. Then season with salt, pepper and a few tarragon leaves, snipped into the salad with sharp scissors. Mix gently and serve at room temperature.