Heat a grill to high. Toss the tomato halves with some canola oil and season with salt and pepper. Grill until the tomatoes are charred and softened, turning once or twice, about 5 minutes total.
Combine the grilled tomatoes, vinegar and chipotles in a food processor and pulse a few times to combine. Add the garlic, onions, cilantro, oregano and some salt and pepper and pulse until slightly smooth.
Put the yogurt in a medium bowl and swirl in some of the salsa, being careful not to stir it in completely.
Recipe courtesy of Bobby Flay