Place a griddle pan on a high heat to get it smoking hot. Using a speed peeler, slice your courgettes lengthways into lovely thin ribbons.
Griddle your courgette slices until softened and lightly charred. You can do this in batches if your pan's not big enough to hold them all in one go. As they are so thin, don't worry about turning them over. Place in a bowl and add the drained beans, the chilli and mint.
Rub your mackerel fillets with a little extra virgin olive oil, then season with salt and pepper. Griddle them, skin side down, for 3 minutes until the skin is golden and crispy. Turn them over and cook for another 2 minutes.
Dress the courgettes and beans with the juice of 1 lemon half, a good lug of extra virgin olive oil and some salt and pepper. Toss to coat everything in the dressing.
Serve the mackerel fillets with a pile of the salad and a wedge of lemon to squeeze over the top.
Tip: Try to find some yellow courgettes – they’ll look lovely alongside the green ones.