Cook pasta in a large pot of boiling salted water until al dente, according to package instructions. Reserve 1/2 cup pasta water. Add chickpeas to pot; immediately drain pasta mixture, and return to pot.
Add tomatoes, bocconcini, thyme, oil, and vinegar to pasta. Toss, adding reserved pasta water a little at a time to create a thin sauce that coats penne (you may not need all the water). Season with salt and pepper; toss to combine. Serve, garnished with additional thyme.