Grill the pita on both sides; place on a baking tray. Seal the duck breast; remove excess fat from the pan, season with the spice, hoi sin, honey, ginger & garlic paste, drizzle with honey & orange juice. Remove duck from pan and roast for 8 minutes in a hot oven. Reduce the sauce to a thick syrupy consistency, remove from the heat and allow cooling slightly. Slice the duck breast thinly and mix in the sauce together with the chopped bell pepper and sesame seeds. Put the pita breads on a baking tray, spread with the tomato sauce, grate mozzarella on top to cover. Top up with the duck sauce & bake for a few minutes until mozzarella melts. Serve piping hot sprinkled with extra sesame seeds & coriander leaves.