Steamed aubergine and courgette with chilli dressing

Name: Steamed aubergine and courgette with chilli dressing
Ingredients: 1 aubergine, peeled and cut into 2–3cm/¾–1¼in thick rounds; 1 courgette, peeled and cut into 2–3cm/¾–1¼in thick rounds; 1 tsp salt; 7 baby plum tomatoes; 2 large red chillies, finely chopped; 1 garlic clove, finely chopped; 15g/½oz fresh coriander stalks, finely chopped; 2 spring onions, finely sliced; ¼ tsp salt; 1½ tbsp vegetable oil; 1 tbsp light soy sauce; 1 tbsp rice vinegar; ½ tbsp sugar; 1 tbsp finely chopped spring onion