Don't let the chicken cook too long, or the paste will darken; serve with the sauce and steamed green beans.
In a medium bowl, combine the cilantro-mint sauce and the oil. Arrange the chicken in a nonreactive dish. Spread the green paste all over each piece of chicken.
Heat a well-oiled grill set over medium-high heat until very hot. Season chicken with salt and pepper. Cook until meat is cooked throughout, about 4 minutes per side. Serve.