Arrange the tomatoes and cheese in a slightly overlapping spiral on a platter. Intersperse the half basil leaves among the cheese and tomatoes. Sprinkle on the yellow bell pepper. Combine the oil and vinegar in a small bowl. Drizzle over the tomatoes and cheese. Sprinkle the salad with salt and pepper. Let stand 10 minutes at room temperature to allow flavours to meld, and then serve.
Note: Mozzarina cheese is similar to bocconcini cheese in texture, but is much larger in size. You’ll find it in the deli department cheese showcase.