Grill the sausages over high heat until they are deep brown in color and have a crispy skin. Remove from the grill and slice into slices. Arrange the slices around the plate and drizzle with the mustard sauce. Place about 1/4 of the confit in the center and garnish with deep fried potato sticks.
Saute the onion, peppers and potatoes in the olive oil until caramelized. Deglaze with the vinegar then add the thyme and season with salt and pepper. Combine all ingredients except the whole grain mustard in a double boiler and whisk over heat until the mixture becomes thick. Strain into a bowl through a fine strainer and allow to cool. Whisk in the whole grain mustard and season with salt and pepper.