Position the rack in the center of the oven and preheat the oven to 275°F. Line an 8-inch square pan with foil, allowing some foil to hang over the edges of the pan, then spray the foil with nonstick spray.
In a large bowl, combine the cereal, nuts, cherries, flaxseeds, and salt. Mix in the orange zest. Add the syrup and stir to coat. Transfer the mixture to the prepared pan.
Bake for 30 minutes, gently stirring the mixture occasionally with a silicone spatula to coat with the syrup. Pat the mixture firmly into the pan with a metal spatula. Continue baking (without stirring) until the mixture is golden brown and still pliable, about 40 minutes.
Cool in the pan on a rack for 25 minutes. Using the overhanging sides of the foil, lift the mixture out of the pan and press firmly on the mixture to help compact it on all sides. Then, using the bottom of the pan, gently press on the top of the mixture to compact it more. Cool on the rack until barely warm, about 10 minutes.
With the foil still attached, cut the nut and cereal sheet into 12 bars with a large sharp knife. Allow the bars to cool completely on the rack.
Store the bars in an airtight container at room temperature. Remove the foil before serving.