In a medium bowl, stir together the yogurt, scallions, jalapeno, garlic, cucumber, and most of the cilantro and mint (reserving a little to sprinkle on top as a garnish) until well blended. Add salt and pepper to taste.
Cover and chill for at least one hour.
When you are ready to serve, transfer the dip to a serving bowl and top with the reserved cilantro and mint.
Serve with an assortment of raw vegetables and/or pita chips.