Using a sharp knife, slice the zucchini lengthways into ½ cm thick strips.
Preheat a chargrill pan over high heat.
Brush zucchini with olive oil and place onto the chargrill, season with sea salt, and cook until caramelised, about 45 minutes per side. Remove and set aside on a warm tray.
Brush cavolo nero leaves with olive oil, add to the chargrill and cook, turning occasionally until lightly charred and wilted. Remove to the tray.
Repeat with the spring onions.
Assemble the Salad
Coarsely chop the spring onions and kale.
Mix with the zucchini, seasoning to taste with sea salt and freshly ground black pepper.
Place into a serving bowl, crumble over the feta cheese.
Dress with lemon juice and extra virgin olive oil.