In the bowl of your crockpot, combine the chicken stock, quinoa, onion, carrots, pesto, red pepper flakes, sage, and a pinch each of salt and pepper. Add the parmesan rind. Cover and cook on low for 4-5 hours or high for 2-3 hours. About 30 minutes before serving, stir in the lemon juice and zest, kale, and beans. Divide the soup among bowls and top with parmesan. Serve with a hunk of bread.