Barbecued vegetable salad

1 large fennel bulb, trimmed and cut into 1cm slices lengthwise

2 red capsicums, quartered, seeds and membranes removed

4 zucchini, cut lengthwise into 1/2 cm slices

2 large red onions, cut into 8 wedges each 6 green onions, trimmed

12 asparagus, woody bottom parts snapped off

Handful basil leaves, shredded

Grated zest of 1 orange

1 tablespoon drained capers

cup (60ml) red wine vinegar

3 large cloves garlic, finely chopped

1 teaspoon dried oregano

1 teaspoon ground cumin

1 teaspoon powdered mustard

1 teaspoon chilli flakes

cup (125ml) extra-virgin olive oil

Juice of 1 orange