Lay the aubergine out in one layer on a large baking sheet. Brush sparingly with vegetable oil, then season generously. Grill for 15 mins, turning twice and brushing with oil until the slices are softened and cooked through. Meanwhile, whizz the bread into crumbs. Add 2 tsp oil and whizz briefly again, to coat.
Spread a couple of tsps of houmous on top of each slice of aubergine. Tip the breadcrumbs onto a large plate, then press the houmous side of the aubergines into the crumbs to coat. Grill again, crumb-side up, for about 3 mins until golden.
Toss the walnuts, parsley and cherry tomatoes in a bowl, season, then add the lemon juice and olive oil and toss again. Serve the grills with the salad, a dollop more houmous and some pitta bread.