In a large bowl, combine the stone fruit with the Garnatxa vinegar and 3 teaspoons granulated sugar. Toss to coat the fruit in the vinegar and sugar, cover and let macerate for 30 minutes at room temperature.
To make the orange whipped ricotta, combine the ricotta, extra virgin olive oil, orange zest, sugar and fleur de sel in the bowl of a food processor. Blend until smooth, about 30 seconds to one minute. Transfer the ricotta to a bowl and refrigerate until ready to use.
To assemble the toasts, slather each toast with a generous layer of orange ricotta, arranging the cheese-covered toasts on a serving platter. Divide the reserved macerated stone fruit between the toasts, mounding the fruit on top of the ricotta. Don't waste the fruity vinegar syrup leftover in the bowl; drizzle it over the toasts as a garnish. Serve immediately.