Preheat a grill.
Grill the sausage on both sides until golden brown and cooked through, about 10 minutes per side. Brush onions and peppers with the oil and season with salt and pepper. Grill the onions and peppers until soft, about 3 to 4 minutes per side. Remove the sausage from the grill and slice into 1/4-inch thick slices. Remove the onions, separate into rings, and roughly chop. Remove the peppers and slice into 1/8-inch thick slices.
Heat grill to high. Brush dough with olive oil, season with salt and pepper and grill for 2 to 3 minutes or until golden brown. Turn over and grill for 1 to 2 minutes. Remove from the grill and place on a flat surface.
Divide the fontina cheese among the 4 pizza rounds. Divide the sausage, onions and peppers over the cheese. Place the pizza on the grill, close the cover and grill until the cheese has melted, about 3 to 4 minutes. To finish in the oven, preheat the oven to 450 degrees F. Place the pizza on sheet pans and bake until the cheese has melted, about 5 to 10 minutes.
Mix together the ricotta, extra-virgin olive oil, and oregano in a small bowl and season with salt and pepper, to taste. Remove the pizzas from the oven and drizzle with Basil Vinaigrette. Top with dollops of the ricotta cheese mixture and let rest for 5 minutes. Slice and serve.
Combine all ingredients and blend until smooth. Adjust seasoning with salt and pepper, to taste.