Preheat an outdoor grill for high heat.
Bring a large pot of salted water to a boil, and cook potatoes 10 to 15 minutes, until tender but firm. Drain, and transfer to a medium bowl.
In a small bowl, mix canola oil, vinegar, Dijon mustard, celery salt, and pepper. Toss 1/2 the mixture with the potatoes.
Arrange potatoes in a single layer on a sheet of foil, and place on the prepared grill. Turning occasionally, cook 7 to 9 minutes, until lightly browned. Remove from heat, and cool. Toss with remaining oil mixture to serve.