Slice the tomatoes in chunks – they don’t have to be the same shape, just approximately the same size.
Slice the onion into thin half moons – as thin as you can manage.
Toss onions, tomatoes, and chopped herbs together and dress with a couple of good glugs of olive oil and some dashes balsamic vinegar. Sprinkle with sea salt (as good a finishing salt as you have – and don’t be shy about it) and freshly cracked black pepper. I always do this to taste but if you want a guide just use 3 parts oil to 1 part vinegar, toss, taste, and adjust. Toss carefully...you don’t want battered tomatoes!