Heat oven to 450 F. Roll the pizza dough into a 10X14-inch oval on a lightly floured board. Transfer it to a baking sheet. Bake for 8 to 10 minutes, or until lightly browned.

Meanwhile, in a medium skillet, heat the oil over medium heat, and stir in the garlic and lemongrass paste; cook for 1 minute. Add the chicken and soy sauce; stir-fry over medium-high heat until the chicken is cooked through. Remove from heat. Place the carrots in a small bowl and stir in a pinch of sugar and the vinegar.

Spread the chicken mixture over the baked dough, then sprinkle it with the carrots, grapes, cilantro, and jalapeño slices. Cut the flatbread into 8 square pieces.