Heat 1 cup (250ml) cream in a saucepan until just barely simmering. Add the chocolate and stir until melted. Transfer to a bowl. Press plastic wrap directly onto the surface of the chocolate mixture to prevent a skin from forming. Refrigerate until firm, about 1 hour.
Soak the tapioca in 2 cups (500ml) cold water for 30 minutes. Drain.
Combine the remaining 1 cup (250ml) cream, the milk, sugar, orange zest and vanilla bean and seeds in a saucepan. Add the tapioca and bring the mixture to a boil. Reduce the heat and simmer for 25 minutes. Transfer to a bowl to cool, then refrigerate until set, about 30 minutes.
Using damp hands to prevent the mixture from sticking to them, shape the tapioca into golf-ball-size mounds, then flatten. Insert a spoonful of the chocolate mixture into the center and reshape the ball, enclosing the chocolate. Place on a parchment-lined baking sheet.
Heat the canola oil in a deep fryer to 350 degrees F (180 degrees C).
Put the flour, eggs and panko in three separate bowls. Dredge each tapioca ball in flour, then dip in the egg mixture and coat with breadcrumbs. Fry until golden brown, 1 to 2 minutes. Transfer to a plate lined with paper towels to drain.