Prepare the dressing first to allow the flavors to meld.
In a small non-metallic bowl, whisk together the olive oil, raspberry vinegar, and caster sugar.
Set aside to let the sugar fully dissolve.
Prepare the tomatoes by cutting each one into 6 wedges. Carefully scoop out and discard the seeds, then place the tomato wedges into a large mixing bowl.
Hull the strawberries and slice them into quarters.
Add them to the bowl with the tomatoes.
Finely slice the mint leaves into thin ribbons (a chiffonade) and add them to the bowl.
Just before serving, pour the dressing over the salad, sprinkle generously with sea salt, and toss gently to combine.
Serve immediately to enjoy its fresh, crisp texture.