Grilled Swordfish Kebabs with Parsley-Olive Salsa

2 tablespoon(s) extra-virgin olive oil

2 tablespoon(s) water

1/2 teaspoon(s) grated lemon zest

2 tablespoon(s) lemon juice

1/4 teaspoon(s) crushed red pepper flakes

1 red onion , cut into 20 wedges

1 1/2 pound(s) swordfish or halibut (1-inch thick) , skin removed, cut into 20 chunks 20 mixed baby bell peppers (or 20 pieces of cut-up bell peppers)

Olive oil cooking spray

1/2 teaspoon(s) kosher salt

1/2 teaspoon(s) freshly ground white or black pepper