Peel jícama and cut enough into 1/4-inch dice to measure 1/2 cup. In a food processor pulse dates to a paste and transfer to a bowl. Stir diced jícama, lime juice, scallion, and mint into dates and season with salt. Date mixture may be made 1 day ahead and chilled, covered.
Cut remaining jícama into 1/4-inch-thick slices and cut each slice into as many 1 1/2-inch triangles as possible. Jícama triangles may be made 1 day ahead, wrapped in damp paper towels, and chilled in a sealable plastic bag.
Top jícama triangles with some date mixture and garnish with small mint leaves.
