Thread a piece of mozzarella onto the skewer. If you have a large basil leaf, fold it into half or thirds, and snuggle it next to the mozzarella (oversized leaves can be halved or even cut into thirds). Affix a tomato onto the skewer's base.
Arrange all assembled skewers on a plate or tray. Lightly drizzle with balsamic vinegar and sprinkle with finishing salt.