Pre-heat oven to 350 degrees and place all four acorn squash halves on a 9 x 13 baking pan or glass baking dish.
Rub the insides of the squash with olive oil and half of the salt and pepper (1/2 teaspoon salt and 1/4 teaspoon pepper.) Flip squash cut side down then roast in the oven until fork tender, 20-25 minutes.
While squash is roasting, heat chorizo in a large skillet over medium high heat and stir frequently. Continue cooking 2-3 minutes or until oils start to release.
Remove chorizo from pan using a slotted spoon and let drain on a plate covered with paper towel.
Add diced onion to the warm pan and sprinkle in remaining 1/2 teaspoon salt and 1/4 teaspoon pepper. Cook, stirring frequently, until onion becomes translucent about 5-7 minutes.
Stir in cooked farro, diced tomatoes, smoked paprika and cayenne. Cook until heated through, 4-5 minutes.
Add green peas and cook until bright green - 1-2 minutes. Remove pan from heat.
Scoop farro and chorizo mixture into all four halves of the squash. Feel free to fill the squash up high!
Sprinkle each half evenly with shredded Manchego cheese.
Bake until cheese is brown and bubbly, 15-20 minutes.