Let the cooked freekeh cool to room temperature. Place it in a large mixing bowl.
Heat the grill to medium-high heat, and grill corn for about 8 minutes, or until lightly charred on all sides. Remove from grill and let cool.
With a sharp knife, remove the kernels from the corn cob, and place in the bowl with the freekeh.
Add the sliced tomatoes, and diced peppers to the bowl.
Add the cilantro and scallions, and lightly toss everything to mix well.
Add the avocado and cotija cheese and lightly stir to toss all ingredients.
Season with salt and fresh ground pepper to taste.
Serve immediately, or refrigerate up to 4 hours before serving.