To make these kebabs, start by preheating your oven to 400°F. Line a baking sheet with parchment paper and set it aside.
Next, prepare the chicken mixture. Add the roughly chopped red onion and red bell pepper to a food processor and pulse until finely minced. Transfer the mixture to a large bowl and use a paper towel to squeeze out as much liquid as possible — this step is important, so don't skip it!
Then, add in the ground chicken, minced garlic, paprika, oregano, cumin, crushed red pepper flakes, kosher salt, ground black pepper, chopped parsley, and tomato paste. Mix everything together until fully combined.
Now, it's time to assemble the kebabs. Lay your stack of flour tortillas flat on the counter and trim off the rounded edges so that you're left with rectangles. Spread the chicken mixture evenly across each tortilla, then stack them on top of one another.
Cut the stack into four equal pieces lengthwise, flip them, and insert a wooden skewer through each piece as shown. Then, slice again and lay each kebab flat on your prepared baking sheet.
Transfer the baking sheet to the oven and bake for 15 minutes. While the kebabs are baking, prepare the garlic parsley butter by melting the salted butter in a small saucepan over low heat and stirring in the minced garlic and chopped parsley.
After the initial 15 minutes of baking, remove the kebabs from the oven and brush them generously with the garlic parsley butter on all sides. Return them to the oven and bake for another 20 minutes, or until they are cooked through and golden brown. If needed, you can rotate them once more and bake for an additional 10 minutes to get them extra crispy.
Once done, remove the kebabs from the oven and carefully remove the skewers. Pull them apart and serve alongside tzatziki, a fresh salad, or your favorite dipping sauce — and enjoy!