Put the duck breasts, skin side up, on a chopping board and slash in three or four places, going through the skin and about half way down through the meat. Season with salt and black pepper.
Place a nonstick shallow pan over a moderate heat, pour in the oil, then place the duck, skin side down, in the pan and let the skin brown lightly.
Turn the duck over, then cover the pan with a lid and let the breasts cook over a moderate heat for 7 or 8 minutes until they are brown outside and nicely pink within.
Cook the peas for 4 or 5 minutes in boiling water until tender, then drain them in a colander. Trim the radishes and cut them in half. Halve the apricots and discard their stones.
Remove the duck breasts to warm plates to rest. Add the radishes, apricots and drained peas to the pan, together with a little more oil if necessary.
As soon as they are hot, add the red wine vinegar and butter and toss the apricots and radishes around in the butter and vinegar till all is glossy.
Spoon the peas, apricots, radishes and pan juices over the duck breasts and serve.