Directions:

• Thaw the flatbread overnight at room temperature.
• Line a sheet pan with parchment paper, and spray with pan release.
• Preheat the oven to 400° F.
• In a large bowl, prepare the brine by stirring together the sugar, white vinegar and water until the sugar dissolves. Cover and set aside.
• Rinse the onions under running water. Drain well in a colander.
• Cut the onions in half, then dice them into ½-inch pieces.
• Mix the onions into the brine. To marinate, cover and refrigerate until needed. This may be prepared a day in advance.
• Rinse the cilantro under running water, and drain it in a colander. Further dry it with paper towel.
• Cut away the thick stems of the cilantro bunch, then finely chop. Refrigerate until ready to use.
• Combine the mayonnaise, yogurt, rice vinegar, honey, cayenne pepper and red pepper flakes in a large bowl. Add the tuna, and using fresh gloves, crumble it into small pieces. Mix gently until all of the ingredients are combined.
• Place 8 flatbreads on a full-size sheet pan. Top each flatbread with 2 oz. of the tuna mixture; spread it to cover the top of the flatbread. Top with 1 oz. of the cheese.
• Bake at 400° F for 7–8 minutes. Remove the flatbreads from the oven, and top with 1 Tbsp. of the drained pickled onion. Sprinkle ~½ tsp. of chopped cilantro on top of each flatbread to garnish.