Grilled Mediterranean Beef Kebabs

Name: Grilled Mediterranean Beef Kebabs
Ingredients: 1 Large Onion (roughly chopped); 1/4 Cup Water; 1/3 Cup Olive Oil; 6 Cloves Garlic; 1 Tablespoon Worcestershire Sauce (be sure to use gluten-free worcestershire sauce, if you want to keep this recipe gluten-free!); 2 Teaspoons Dried Rosemary; 1 Lemon (zested and juiced); 2 Teaspoons Kosher Salt; 1 Teaspoon Ground Black Pepper; 2 1/2 Pounds Sirloin Steak (cut into 1 1/2 inch cubes ); 2 Red Peppers (seeds removed and cubed); 2 Red Onions (peeled and cubed)