Preheat the oven to 450 degrees F. Pierce the sausages a few times with a fork and arrange on a baking sheet. Bake until lightly browned and cooked through, about 15 minutes. Let cool.
Meanwhile, heat 1 tablespoon peanut oil in a large nonstick skillet over medium-high heat. Add the onion, bell peppers, garlic, 1/2 teaspoon salt and a few grinds of pepper; cook, stirring occasionally, until the vegetables are soft and lightly browned, about 7 minutes. Transfer to a plate to cool.
Heat 2 inches of peanut oil in a large pot or Dutch oven over medium heat until a deep-fry thermometer registers 340 degrees F. Whisk the cornmeal, 1 cup flour, the sugar, baking powder, mustard powder, oregano, red pepper flakes and 1 teaspoon salt in a large bowl. Whisk the milk and eggs in a medium bowl. Add the milk mixture to the flour mixture along with the parsley and whisk to make a smooth batter. Stir the peppers and onions into the batter.
Stick each sausage on an 8-inch wooden skewer. Put the remaining 1 cup flour in a shallow dish. Working in batches, dredge the sausages in the flour, turning to coat, then dip in the batter to coat, letting the excess drip off. Fry the sausages (sticks included) until golden brown, about 4 minutes. Remove to a paper towel-lined plate and sprinkle with salt. Serve with the marinara sauce.