Cut bell peppers in half lengthwise; discard seeds and membranes. Place pepper halves, skin sides up, on a foil-lined baking sheet; flatten with hand. Broil 15 minutes or until blackened. Place in a zip-top plastic bag; seal. Let stand 15 minutes. Peel and finely chop.
Place coriander seeds in a small skillet; cook over medium heat 3 minutes or until seeds are lightly browned and fragrant, shaking pan frequently. Transfer seeds to a spice or coffee grinder, and process until finely ground.
Heat oil in a medium nonstick skillet over medium heat. Add onion; sauté 8 minutes or until translucent. Add coriander, crushed red pepper, and garlic; sauté 3 minutes.
Combine onion mixture and roasted bell pepper in a medium bowl. Stir in red wine vinegar and next 4 ingredients (red wine vinegar through black pepper). Cover and refrigerate 30 minutes. Stir in cilantro.