When guests visit for days, I often take them for a jaunt to New Haven. It’s about a half-hour drive from Fairfield, and offers the Yale University Art Galleries. New Haven also has great restaurants. I’m adding another to my list. The owners of Olea, a Spanish-Mediterranean restaurant, invited me to experience the chef’s tasting menu. Olea has a calming, contemporary atmosphere, that looks upscale, but soon transformed into a buzz. In the site of the former Ibiza, Olea shares a heritage with that acclaimed Spanish restaurant; the new chef/co-owner is the former chef of Ibiza, and worked at Meigas and Meson Galicia in Norwalk with chef Luis Bollo, when it was the best Spanish restaurant in the Northeast. Olea is now assuming that mantle.  The Mediterranean food reveals classic technique, with fun molecular gastronomy touches of foams and soils, bound in a love of craft and of cooking for restaurant guests. The meal began with a sampling of three tapas on a rectangular plate. A clear glass of pureed orange-hued gazpacho balanced sweetness and acidity (a quality in many of the dishes to follow). A codfish …