This historic eatery, a former working-class bolthole, is enjoying a second lease of life under the auspices of its owners. On one side is the Rio, a cultural venue which serves tapas to a backdrop of live music, while on the other is a gourmet restaurant graced by a spacious dining room, which commands a view of the kitchen and sports a vintage counter and bench seats, exposed timbers, bare stone walls and works of art. Chef Denis Martin expertly crafts recipes focused on Mediterranean delicacies, such as red mullet and a soft bread with squid ink, crunchy vegetables, shellfish and a stock of fishbones, or octopus in preserved tomatoes and olives. Heroically wondrous cooking…