"Here's the idea: we take the liquid produced by marinating fresh cherry tomatoes in salt, pepper and vinegar, and strain it into a pan. We then take this already delicious juice, and make it even more so by reducing it over heat. This intensified liquid is poured back into the tomatoes and we have a great fresh tomato relish that we can use to top grilled meat, chicken, or fish."
Stir tomatoes, olive oil, red wine vinegar, garlic, salt, and pepper together in a bowl. Cover the bowl with plastic wrap and refrigerate until flavors blend and juice accumulates, about 30 minutes.
Strain accumulated juices into a small skillet and transfer tomatoes back to the bowl. Cook juices over medium heat until liquid reduces and sauce has a syrup-like consistency, 2 to 3 minutes. Pour sauce back over tomatoes into bowl and stir.