Stir the vinegar and garlic together and let sit for 5-10 minute, then mix in the mayonnaise and mustard.
French Friesd
Scrub the potatoes but don't bother peeling. Cut the potatoes into 1/4" thick slices, then turn the slices onto their sides and cut into 1/4" strips. I find this easiest to do if I slice 1/4" off the ends first and cut the ends into 1/4" strips separately. Then you can stack the first 1/4" slices and cut through them all at the same time to form the strips.
Soak in a bowl of hot water for 10 minutes while you heat the oven to 450 F. Drain the potatoes and pat dry with a towel or paper towels. Mix in a bowl with the oil and salt.
Spray a baking sheet with olive oil (I like this Misto Olive Oil Sprayer) and spread the potatoes out in a single layer as much as possible. Bake 30 minutes or so, then turn over and bake another 5-10 minutes. Watch them the last few minutes as they can quickly go from perfect to overdone!