In the bowl of a food processor add grilled tomatillos, onion, avocado, cilantro and garlic. Cut stem from jalapeños and cut in half, scoop out seeds and add flesh to processor. Juice grilled lime and add to processor. Pulse until combined but still a little chunky. Season with salt and garnish with additional cilantro and chopped red onion. Serve immediately with tortilla chips or chill until ready to use.