This is incredibly straight-forward, but also usually a hit at parties.
All you really need is patience.
The only way these would be easier to make would be if you used the tomatoes whole and raw, in which case I would have just called these Caprese Skewers.
Unfortunately for me, the only tomatoes I could find in late May were still largely an under-ripe orange color and not very sweet. To combat this I sliced them all in half, spread them out on a sheet tray, sprinkled them lightly with both salt and sugar, drizzled them with olive oil, and then slow-roasted them at 200º (F) for two hours.
The resulting tomatoes will be sweeter and have a richer flavor, akin to sun-dried tomatoes, but still a bit juicy. Then it's just an assembly line of tomato half, bocconcini mozzarella (which I marinated overnight in good olive oil, salt, dried oregano, and some leftover oil from my marinated sun-dried tomatoes, but plain would be delicious as well) a torn piece of basil, and capped with the other half of tomato.
Super simple bites that are tasty at room temperature.
Note: you do not want to make these more than 24 hrs ahead of time, especially if you are using fresh tomatoes. The mozzarella needs to be refrigerated before serving, but if raw tomatoes spend too much time in a refrigerator they become mealy and unpleasant to eat. If you are roasting the tomatoes as I did here, refrigerating overnight should be fine.
Just don't serve the skewers cold from the fridge.