Take one bite of the Campeche shrimp salad ($6.95) at Seรฑor Rita’s Margarita Village (2409 Montrose, 713-526-7482), and you’ll wonder why you’ve never tasted this combination of ingredients before. Served in an oversize margarita glass large enough for two, the salad includes shrimp, cocktail sauce, onion, cucumber, bell pepper and shredded lettuce. But it’s the addition of mango and watermelon pieces that makes this a most unusual and refreshing dish. And the large portion of guacamole, which sits on top, adds another level of flavor.