Combine first 4 ingredients in a small bowl; stir well. Cover and chill.
Preheat oven to 350°.
Combine 2 tablespoons Romano cheese, oregano, mustard, pepper, and ricotta cheese in a food processor, and process until smooth. Spoon into a bowl, and stir in artichokes and crabmeat. Divide mixture evenly among the chile halves, and sprinkle with 1 tablespoon Romano cheese. Place stuffed chiles on a baking sheet, and bake at 350° for 30 minutes or until lightly browned. Serve chiles with mango salsa, and garnish with cilantro sprigs, if desired.
Note: Substitute 4 red or green bell peppers for poblano chiles, if desired.