Heat oven to 375 degrees F. Place cherry pie filling in colander and let stand, stirring occasionally to drain thick syrup surrounding cherries.
Meanwhile, unroll crescent dough and separate into 8 triangles. On a parchment-lined baking sheet, line up two triangles so that they are touching on one edge and are mirror images of each other. Pinch them together along the one edge and gently stretch their opposite points about 1 inch further outward on the baking sheet.
Repeat this to pinch together and arrange another two dough triangles; place them so they halfway overlap the first two. Repeat this pattern with pairs of triangles to create a center strip of dough, about 6-inches wide and 12-inches long, with 4 points of dough extending on either side.
Scatter 2/3 cup pecans over center strip of dough; sprinkle with cinnamon sugar. Stir cherries to remove most of thick syrup, leaving about 1 cup of cherry filling remaining. Transfer this amount to mixing bowl; add blueberries and granulated sugar, mixing well. Spoon fruit mixture down center strip of dough, over pecans, leaving a 1-inch border wide all around. Fold up top and bottom ends of strudel to cover ends of fruit filling. Fold in pointed side pieces of dough, alternating each side, to partially enclose filling.
Sprinkle generously with cinnamon sugar and bake 25 – 30 minutes or until golden brown and filling is bubbly. Garnish with chopped pecans, if desired. Cool until warm, or room temperature, before serving.
Nutrition information per serving – calories: 250; protein: 2g; carbs: 33g; saturated fat: 3g; monounsaturated: 6g; polyunsaturated fat: 2g; cholesterol: 0 mg; fiber: 1g; sodium: 227 mg.