Mix the chili, half the mint, lemon zest and juice, oil, zucchini/courgettes and halloumi. Leave to marinate for 30 mins. Soak 8 wooden skewers for 20 mins.
Thread the zucchini/courgettes and halloumi onto the skewers. Cook on the BBQ, or under a grill, for 7-8 mins, turning halfway through and basting with the remaining marinade. Scatter over remaining mint.