Preheat oven to 450°F. Line a 15x10x1-inch baking pan with foil or parchment paper. Place tomatoes, cut sides down, on prepared baking pan. Place onion, garlic, and chile peppers on baking pan. Drizzle vegetables with olive oil. Roast about 20 minutes or until tomato and pepper skins are charred and onion is tender. When vegetables are cool enough to handle, pinch tomato skins to remove and use a knife to peel skins from chile peppers. Coarsely chop vegetables.
In a medium bowl, combine roasted vegetables, sweet pepper, cilantro, lime peel, lime juice, oregano, cumin, and salt. Cover and chill overnight.
Tote salsa in an insulated cooler with ice packs.
An insulated cooler with ice packs