Place the cherry tomato halves in a colander and sprinkle them with ¼ teaspoon of salt and toss. Place the colander over a bowl and let the tomatoes let off liquid. Set aside.
Heat a small skillet over medium heat. Add olive oil. When the olive oil is fragrant, add the garlic and lemon rind to the pan and season with ¼ teaspoon of salt. Sauté the garlic until fragrant. Remove from heat and let the garlic cool for 5 minutes.
Next, add the mayo, balsamic vinegar, mustard, and water to a bowl and whisk to combine.
Discard the lemon rind and add the olive oil and garlic to the mayo mixture. Whisk to combine.
Assemble the salad. Discard the excess tomato liquid. Add the tomatoes, mozzarella balls, basil leaves, and red onion to a salad bowl. Pour the mayo dressing over the ingredients and toss until everything is covered in the dressing.
Top with the remaining salt and pepper, toss, and enjoy.