Cut the cauliflower into florets and place in a food processor. Blitz until it looks like rice. Alternatively you can grate the cauliflower florets.
Heat the olive oil in a frying pan on a medium heat and cook the cauliflower rice for about 10 minutes, stirring occasionally so not to brown it.
Remove from the heat and put aside.
Preheat the grill to high. In a large bowl, whisk the olive oil, lemon juice and zest.
Cut the zucchini into ribbons using a vegetable peeler or a sharp knife.
Place the zucchini ribbons into the bowl with the dressing to coat them.
Arrange the zucchini ribbons on a baking tray (line with parchment paper) and place under the hot grill for about 2 minutes each side until golden.
Add the spring onions, parsley and mint to the cauliflower rice and gently stir.
Crumble the Feta cheese into the cauliflower mixture and mix. Season with the black pepper.
Spoon the cauliflower rice into a bowl and top with the grilled zucchini slices. Drizzle with the remaining dressing and sprinkle with sumac.