When ready to assemble, bring olives and cheese to room temperature for about 15 minutes to melt the olive oil which will have solidified in the fridge, and add the tomatoes. Stir or shake to completely cover them in the marinade.
Thread an olive, a tomato and piece of cheese onto skewers, with the cheese on the bottom so they'll stand upright, or offer separately in three bowls, with tooth picks on the side.
These may be served right away, or kept in the fridge until ready. Again, allow to sit at room temperature for about 15 minutes because olive oil solidifies when refrigerated.
Notes:
These are quick to make but need enough time for the pieces to marinate (12 to 24 hours).