For the tomato salad

1. Prepare your tomatoes by slicing any that are large or medium-sized and halving small ones
2. Mix the herbs with the diced red onion
3. On a large platter, start layering the tomatoes, mixing colours and sizes
4. Scatter each layer with some of the herb-onion mix and ground black pepper, do this until all of the tomatoes are used. Cover and chill for a few hours
5. Whisk all of the dressing ingredients, then drizzle over the salad

For the seared tuna

1. Trim the tuna as required and pat dry with kitchen roll
2. Spread the sesame seeds on to a plate and press the tuna into the seeds, ensuring the front and back surfaces are fully covered. You don’t need to coat the edges
3. Using a large frying pan, heat a little oil and, once hot, add the tuna. Sear for 30 to 60 seconds on all sides, like you would with a piece of beef before roasting
4. Remove from the pan and allow to rest for 10 to 15 minutes