Preheat oven to 400°F (200°C).
Peel and cut potatoes into 3/4-inch cubes; place in a large roasting pan. Peel the red onions, trim the tops and bottoms, cut in half lengthwise, them into wedges, and again into 3/4 inch cubes. Add them to the potatoes. Drizzle liberally with olive oil and season with salt and pepper. Toss well. Roast for 20-25 minutes, tossing occasionally to keep them from sticking.
Cook peas separately.
While the potatoes are cooking, preheat gas grill to high. If using charcoal, light fire to one side.
Place vinegar, mustard, shallot, honey, salt, pepper, 1/4 cup olive oil and canola oil in a bowl, and emulsify using an immersion blender. Add the parsley and mint, and blend again to make it as smooth as possible.
Brush the chops with olive oil and season well with salt and pepper. Place chops on grill; reduce heat to low and cover if using gas. If using charcoal, place chops on the cool side of the grill and cover. Cook lamb ribs for two (2) minutes per side.
Divide potatoes and onions among 6 dinner plates and spoon some peas over the top. Arrange three chops on each plate and drizzle with the vinaigrette.