Mexican Chicken Sandwiches
In a small mixing bowl, whisk together mayonnaise, lime juice and lime zest; season with salt and pepper and set aside. Heat oil in a small skillet over medium heat; add beans and onion. Cook 5 min. Move bean mixture to a medium mixing bowl and add stock, cilantro and cumin; mash to a paste with salt and pepper to taste. Set aside. Season chicken with chili powder, cayenne, salt and pepper to taste; grill over high heat, covered, until cooked through (about 10 min.), turning once. Remove from grill; cover chicken with cheese and cover loosely with foil. Let stand 5 min. Spread half of each roll with bean paste and other half with a generous amount of lime mayonnaise. Top each roll with a piece of chicken, an equal amount of tomato and a generous dollop of guacamole. Serve immediately.