Combine the tomatoes, scallions, cilantro, red wine vinegar, garlic, lime zest and juice (to taste) and chile pepper (to taste) in a medium serving bowl. Add the salt and pepper. Stir to combine. Let sit at room temperature for 10 minutes, then stir again.
Divide the salsa into 2 bowls. Serve one as traditional salsa. To the other bowl, add the avocado and mix to combine.