Place the metal chopping blade inside the food processor and turn the processor on. With the blades running, drop the jalapenos down the food processor chute and process until finely diced. With the blades still running, add the quartered onions and process until diced. Open the food processor and add the tomatoes. Close the food processor and pulse till the tomatoes are finely diced. Open the food processor scrape down the sides and add the lime juice and cilantro. Pulse until the cilantro is minced. Pour the salsa into a bowl and add salt to taste.