Mango, Tomato & Avocado Salad

Working over a bowl to collect any juices, remove the skin from the mango and cut the flesh away from either side of its large, central stone. Cut the flesh into thin, evenly-sized slices and place it on a serving platter. Trim and peel the onion, then cut it in half and slice each half as thinly as you can. Slice the tomatoes thinly, too, then tip them (and any juices) on to the platter together with the onion, add the lime juice and zest and toss gently together to combine. Next, cut carefully around the length of the avocado and pull the two halves apart, then use a spoon to scoop out the stone. Cut each avocado half into slender, crescent-shaped slices and place on the serving platter. Sprinkle over the chopped herbs, drizzle over the olive oil and any juice you saved from the mango (you may need a little more or less oil, depending on the amount of juice present). Toss it all together once more, taking care not to bash the avocado slices too much, and serve.