Prep the fries by tossing them in a large bowl filled with cold water, ice cubes, and about 1 tablespoon salt. Let sit for 30 minutes, then drain and pat dry.
As you prep the other ingredients, you can begin making the fries by heating up frying oil over medium heat to 400F, or until glistening. Fry in small batches until golden. Remove the fries with a slotted spoon to a paper towel lined plate. Try not to stack them on top of each other.
Fry each batch a second time until golden brown and crispy. Season with salt to taste.
Make the garlicky yogurt sauce by combining all ingredients in a bowl. Season with salt and black pepper to taste. Set aside.
Make the herby onions by tossing all ingredients together. Set aside.
If sautéing zucchini, sauté over medium high heat in a large skillet with olive oil. Remove and set aside.
Cut the chicken thighs into bite sized pieces with kitchen scissors. Place in a large bowl with the seasonings and tomato paste. Mix until well combined.
Add the olive oil to the large skillet over medium high heat to warm for 30 seconds. Add the chicken to sauté for 10-15 minutes, until fully cooked.
Layer each flatbread with the garlicky yogurt sauce, baby arugula, sautéed zucchini, cooked chicken, red onions, fries, and freshly chopped mint or parsley. Wrap the bottom in parchment paper to catch any sauce drippings. Enjoy warm!