Cut the salmon into 1 1/2 inch chunks. You are going to need approximately 12 pieces. Cut the peppers into 1 1/2 inch square pieces Cut the red onion into similar sized chunks and separate the layers. Thread your skewers alternately with the onions and peppers, and then the salmon. Leave some room at the base so you can handle them easily. Brush the skewers liberally on both sides with olive oil, and sprinkle with salt and fresh ground black pepper. Cook on a hot grill, turning once, until the fish is cooked through and the veggies are softened a bit. Don't overcook! Serve with a squeeze of lemon.
