In a large mixing bowl, combine the mayonnaise with the cooked chicken until the mixture is well coated.
Add the sliced green onions, dried onion, garlic salt, brown sugar, grapes, and toasted almonds. Stir thoroughly so the ingredients are evenly incorporated throughout the chicken mixture.
Taste the filling and season with salt and pepper as needed.
Place one tortilla on a clean work surface. Spoon one-quarter of the chicken salad onto the tortilla and spread it into an even layer, leaving approximately a 1/2-inch border around the edges.
Roll the tortilla tightly into a log. Repeat with the remaining tortillas and filling.
Wrap each tortilla log securely in plastic wrap, tucking the ends underneath to seal.
Transfer the wrapped logs to the refrigerator and chill for at least 4 hours, or overnight for best firmness and flavor development.
Once chilled, remove the plastic wrap. Using a sharp knife, cut each log into 1/2-inch slices.
Arrange the pinwheels on a serving platter and serve immediately.