In a food processor, combine the olive oil, lemon juice, chopped onion, parsley, paprika, bay leaf, pepper, and 2 tablespoons of water. Process until pureed. Pour into a shallow baking dish, and add the swordfish. Toss to coat. cover and marinate at room temperature for 30 minutes or in the refrigerator for up to 2 hours.
Remove swordfish from marinade and discard the leftover marinade. Drain and blot dry to remove excess marinade. (if desired)
prepare a fire for grill. Away from the heat source, lightly spray the grill rack or broiler pan with olive oil or cooking spray. Position the grill rack or broiler pan 4/6 inches away from the head source.
Thread the fish and the bell pepper, tomato, and onion pieces onto the skewers in alternating layers. Arrange the kabobs on the grill rack or broiler pan and season with the salt. Grill or broil, turning every 2 minutes, until the swordfish is opaque throughout when tested with the tip of a knife. About 5/6 minutes. Serve immediately.