For the skewers, thread alternating pieces of halloumi, pepper, onion and courgette onto eight wooden skewers. Brush with olive oil and heat a griddle pan until smoking. Cook the skewers on the hot griddle for about two minutes on each side.
For the salsa verde, place the parsley, tarragon, chervil, capers, garlic and olive oil into a small food processor. Blend until smooth.
Place two skewers per person onto each of four plates. Drizzle some of the salsa verde onto each and serve with mixed salad leaves.