Soak wooden skewers in water for 15-30 minutes. Preheat grill to medium high heat or 400 degrees. Pat Salmon dry and cut into 1″ cubes. In a small bowl mix 2 tbsp cajun seasoning spice and 1 tsp garlic powder, stir with a spoon. Season both sides of the salmon cubes with cajun spice blend. Gently rub the seasoning in to make sure it sticks to the salmon. Alternate red onion, pineapple chunks, mini bell peppers, and salmon on the skewer until it is full. Repeat process. Spray grill grates with PAM or rub down with olive oil. Place salmon kabobs on grill and cook for 2-3 minutes per side. Remove from grill and serve!