In 10-inch nonstick skillet, heat oil over medium-high heat. Add onion and garlic; cook 6-8 min, stirring occasionally, until onion is tender. Stir in beans and chiles. Cook, stirring frequently, until hot.
Place 1/4 of the bean mixture on center of each tortilla. Top with cheese and tomato.
Fold one end of each tortilla up about 1 inch over filling; fold right and left sides over folded end, overlapping. Fold remaining end down. Place seam side down on serving platter or plate. Serve with salsa and sour cream.