Preheat grill using the two zone or direct/indirect method of grilling. Target 450 - 500 degrees F over the direct side of heat.
Place all the prepared grilled ingredients on a sheet tray including, tomatoes, onion, peppers, and lime. Put the garlic in a small cast iron pan to prevent them from falling through the grate.
Place the ingredients over direct heat. Rotate using long tongs, frequently, until the outside of the ingredients have a charred look and are soft in texture. The peppers should cook in 5 - 6 minutes. Followed by the tomatoes, lime, and garlic at 10 minutes. The onion should be done in 12 - 15 minutes depending on the size.
Let the tomatoes and peppers cool slightly and then remove the skins. Also remove the dense stem area inside the tomatoes as well if they have any.
Add the roasted ingredients into the blender. Squeeze the lime juice into the tomato mix. Also add the cilantro and salt. Pulse a few times and season to taste. Add more lime if lacking acidity and salt to your preferred taste.