Preparation Combine 1 cup mint leaves, 1 cup cilantro leaves, minced jalapeño chili and chopped onion in work bowl of processor. Process until very finely chopped. Mix in cider vinegar. Add mayonnaise and process just until combined. Season mayonnaise to taste with salt and pepper. (Mayonnaise can be prepared 3 days ahead. Cover tightly and refrigerate.)
Preparation Combine 1 cup mint leaves, 1 cup cilantro leaves, minced jalapeño chili and chopped onion in work bowl of processor. Process until very finely chopped. Mix in cider vinegar. Add mayonnaise and process just until combined. Season mayonnaise to taste with salt and pepper. (Mayonnaise can be prepared 3 days ahead. Cover tightly and refrigerate.)