1.Place burghul in medium heatproof bowl; cover with boiling water. Stand 15 minutes; drain. Rinse under cold water; drain on absorbent paper.
2.Cook rice in large saucepan of boiling water, uncovered, about 35 minutes or until rice is tender; drain. Rinse under cold water; drain.
3.Quarter capsicums; discard seeds and membranes. Roast under grill or in very hot oven, skin-side up, until skin blisters and blackens. Cover capsicum pieces with plastic or paper for 5 minutes; peel away skin, then slice capsicum thickly.
4.Boil, steam or microwave squash until tender; drain. Rinse under cold water; drain.
5.Meanwhile, make dressing by placing garlic, oil and lemon juice in a screw-top jar; shake well.
6.Combine burghul, rice, capsicum and squash in large bowl with dressing, onion, nuts and parsley.