Pierce poblano 2 times with the tip of a knife. Place poblano on a foil-lined baking sheet; broil 10 minutes or until blackened, turning occasionally. Place in a zip-top plastic bag; seal. Let stand 15 minutes. Peel and discard skins. Cut a lengthwise slit in poblano; discard seeds and stem. Finely chop poblano.
Combine poblano and remaining ingredients. Refrigerate in an airtight container for up to 2 weeks.