Using a sharp knife, cut horizontally to open out each fillet like a book, then brush all over with harissa and set aside for five minutes to marinate.
Heat a large griddle over a high heat. Toss the asparagus in the oil and sear for two to four minutes until just tender. Toss these in a bowl with the fennel and chickpeas.
Sear the chicken on the griddle for three to four minutes each side until cooked through with no pink meat. Rest for five minutes.
Whisk the lemon juice and oil together with some seasoning and pour over the asparagus salad. Add the coriander and toss well. Slice the chicken and serve on top of the salad.