Preheat your oven to 350 F degrees. Place the tomatoes, onions and garlic on a baking sheet and roast for 15 minutes or just until the onions and tomatoes start to get a little char on them. Remove the baking sheet from the oven and let the tomatoes cool for about 5 minutes. Add the tomatoes, onions, garlic, green chiles, cilantro, lime juice and salt and pepper to a food processor and pulse a few times until you get the desired consistency. Pour in a bowl and cover with plastic wrap (or an airtight container) and refrigerate for 2 to 4 hours before serving.