Place the corn in a heatproof bowl, pour some boiling water over it and blanch for 2–3 minutes. Drain, then transfer to a large bowl. Add the salad mix, onion, tomatoes and cucumber and toss together.
To make the dressing, combine all the ingredients in a bowl and set aside until ready to use.
Heat a non-stick frying pan over a medium–high heat. Spray the lamb with cooking spray, then cook for 2–3 minutes each side or until cooked to your liking. Transfer to a sheet of foil, wrap tightly, and allow to sit for about 5 minutes. Slice the meat into 1 cm thick slices, place into a large bowl, pour over some of the dressing and toss well. (The heat of the meat will help to absorb the flavours of the dressing.) To serve, toss the meat and salad together, drizzling over any remaining dressing, if you like.