Heat broiler. Place tomatoes, poblano chile, onion, garlic, and red pepper (cut side facing down) on a baking sheet; place in oven. Cook until tomatoes and poblano skins begin to blacken, 5-8 minutes.
Remove from oven; turn over tomatoes and poblano. Return to oven, and roast until tomatoes and poblano are charred and tender, 5 to 8 minutes more. Remove from oven; transfer red pepper and poblano chile to a bowl; cover with plastic wrap. Set aside for 10 minutes.
When cool enough to handle, remove skins, stems, and seeds, and place in bowl of a food processor with tomatoes, onions, red-wine vinegar, and pepper. Remove skins from garlic, and add to food-processor bowl. Puree until just barely smooth.