Cut onions and bell peppers into 1 1/2inch squares and place in large mixing bowl. Soak bamboo skewers for 30 minutes in water so that they will not burn. Drizzle olive oil and sprinkle vegetables with granulated garlic and kosher salt to taste, mix well. Assemble skewers starting with bell pepper pieces and onion pieces between jalapenos and continue until skewers are full. On medium heat, grill skewers for approximately 10 minutes on each side until desired doneness has been attained.