Mix 1/2 cup sugar, 1 tablespoon sweetened cocoa powder and 1 teaspoon cinnamon in a bowl. Cut 1 pound pizza dough into 24 pieces. Place 3 dark chocolate chunks in the middle of each piece, pinching the dough to enclose; roll each into a ball. Working in batches, fry the dough balls in 2 inches of 350 degrees F vegetable oil, turning, until golden, about 4 minutes. Transfer to paper towels to drain, then roll in the sugar mixture while still warm.