In a non-reactive bowl, whisk together the oil and vinegar until completely combined. Add the garlic, half the tomatoes and half the tarragon. Season with salt and pepper and stir to coat. Cover and chill 6 hours.
Strain the mixture through a fine sieve and discard the solids. Stir in the remaining tomatoes and tarragon. Serve over slices of fresh tomato.
BYOC: Use your favorite herb here and tailor this dressing to the meal or your family's favorite flavors... fresh thyme oregano, basil, chervil, parsley, anything goes! Try serving this sweet and tangy dressing tossed with fresh baby spinach, a baby mesclun mix or even butter lettuce and blue cheese.