Banners of colorful papel picado decorations flutter above Cafe Sol Azteca's seasonal patio, where a tile mosaic wall echoes the folk art hanging in the main dining room. Inside, chefs whip up guacamole—ranked among the best in the city by Boston Magazine—and simmer chicken in rich chocolate-infused mole sauce, or tuck tender cactus into salads. These specialties match with more than 15 varieties of margaritas, such as the blue frozen margarita and the Three Generation Margarita with a glass rim that the kitchen staff rolls in salt uphill both ways.