Halve tomatoes across the centre and gently squeeze to remove seeds and excess juice. Dice the flesh and place in a bowl. Add basil and season well with sea salt and freshly ground black pepper. Drizzle over 1 tablespoon of the oil, toss and set aside for 15 minutes to allow the flavours to develop.
Meanwhile, drain the bocconcini and slice thickly.
Slice the bread on a slight angle and toast or chargrill on both sides until golden. Remove from grill and rub one side of each slice with the cut side of the garlic, then brush with oil.
Arrange a couple of slices of bocconcini onto the bread and top with tomato.