If using wooden skewers, soak in water for at least 30 minutes.
Cut the salmon fillets into 2.5cm cubes.
In a medium bowl mix together the oregano, olive oil, salt, pepper, garlic, chilli flakes and sesame seeds. Add the salmon, toss to combine and set aside to marinate for 15 minutes.
Prepare the barbecue for direct cooking over medium heat (180°C to 230°C).
Alternate threading the salmon, asparagus and the lemon slices onto the skewers.
Grill the salmon skewers over direct medium heat for 3 to 4 minutes. Using a metal spatula, carefully flip the skewers and grill for a further 3 to 4 minutes on the other side, or until cooked to your liking.
Alternatively, if you have an Elevations™ Grill Rack (Suitable for Premium Gas barbecues only), cook the skewers over indirect medium heat (190°C to 230°C) for 15 minutes, no flipping is required.