Swordfish Kebabs

Ingredients

• 1 cup chopped onion
• 1/4 cup fresh lemon juice (about 2 lemons)
• 2 tablespoons olive oil
• 1 tablespoon minced garlic
• 1 teaspoon salt
• 1 teaspoon ground cumin
• 1 teaspoon paprika
• 1/2 teaspoon black peppercorns
• 1/4 teaspoon crushed red pepper
• 1 pound swordfish, cut into (1/2-inch) cubes
• 1 pint large cherry tomatoes
• 4 poblano chiles, seeded and cut into 1-inch pieces
• Cooking spray