Cut the onglet into 3 cm (1¼ inch) cubes. Remove the fat from the smoked duck breast, slice into 5 mm (¼ inch) thick strips, then into small rectangles. Halve the bulb spring onions.
For the chilli oil, combine the olive oil with the chilli, sesame seeds and pepper.
On a skewer, thread half a bulb spring onion, then alternate meat, duck, tomato, mushroom and finish with another