Preheat oven to 400 °F. Place tomatoes, jalapeños, onion, and garlic on a baking sheet tray. Drizzle about 1-2 Tbsp olive oil over ingredients. Place sheet tray in center of oven and roast for 15-20 minutes until tomatoes begin to soften.
Set oven temperature to broil. Keeping sheet tray in the center of the oven, broil ingredients for 5 minutes until the skins of the tomato and jalapeño are slightly charred.
Allow ingredients to cool slightly. Place roasted ingredients in a food processor (or blender). Add lime juice and pulse a few times until ingredients are combined and tomatoes are still a bit chunky. Season with salt, sugar, and black pepper. Fold in chopped cilantro. Serve warm or store in an airtight container in the fridge and allow to chill.
Notes
*NOTE: For a spicy salsa, keep jalapeño seeds intact. For a mild salsa, remove seeds and center rib.