Cut the salmon.
Cut the salmon into ½” (13mm) cubes. Heat grill to 450ºF (230ºC) or grill pan to medium-high heat. Brush the grates with vegetable oil.
Season the salmon.
Add the cubed salmon to a medium mixing bowl and toss with the oil. Season with the cayenne, onion powder, garlic powder, salt and pepper, tossing to combine and evenly coat the salmon.
Thread salmon onto skewers
Thread salmon pieces and folded lemon slices onto 2 soaked skewers, alternating the salmon and lemon.
Cook the salmon.
Grill the salmon skewers, turning halfway through cooking until the fish is cooked through and has turned light pink color, about 8 to 10 minutes.
Serve the salmon on or off the skewers garnished with fresh chopped herbs with roasted vegetables or a kale salad.