Preheat oven to 220 degrees celsius and line a large oven tray with baking paper.
Combine oil, cumin and pepper in a large bowl, then add mushrooms, zucchini, beetroot and capsicum; toss vegetables to coat. Keep tomatoes aside: put remaining vegetables on the large tray in a single layer.
Bake vegetables for 20 minutes.
Add tomatoes, bake for a further 10 minutes or until all vegetables are tender and well browned. Cool on trays.
Place lentils, roasted vegetables and any roasting juice in a large bowl with salad leaves and coriander; toss gentle to combine.
Top salad with tuna, red wine vinegar and pine nuts to serve.