Cook the potatoes, halving any larger ones, in a pan of boiling salted water for 20 minutes, or until tender. Meanwhile, score the skin of the duck breast at 2cm intervals, then season with sea salt and black pepper. Place the duck skin-side down in a cold non-stick frying pan, then turn the heat on to medium-high. Cook for 8 minutes without moving it, or until the fat is well rendered and the skin is golden and crispy. Turn the duck over and cook for 4 minutes on the other side, then remove to a plate to rest, leaving the pan of duck fat on the heat. Snap the woody ends off the asparagus and add the spears to the potato pan for the last 5 minutes, adding the peas for the last 2 minutes, then drain it all and leave to stream dry. Finely chop the chilli and mint leaves (reserving a few pretty baby leaves), and place in a large bowl. Finely grate in the lemon zest and squeeze in half the juice, add 1 tablespoon of extra virgin olive oil, mix together and season to perfection. Halve the asparagus spears, then tip all the warm vegetables into the dressing and mix well. Divide between your plates, then slice the duck and arrange over the top. Scatter over the reserved baby mint leaves to finish.