• Sour cream or plain Greek yogurt, for garnish
Preheat the oven to 425 degrees. Trim the stem and blossom ends from the zucchini and then slice each lengthwise into 1/2 inch planks. Stack the planks and slice them lengthwise into 1/2-inch-wide strips, then cut the stacks into 2-inch-long pieces.
In a large bowl, combine the chipotle powder, lime zest and coarse salt.
Place 2 heavy baking pans with rims in the oven for 3 minutes to preheat.
When the sheet pans are hot, remove from oven and quickly drizzle with a teaspoon of canola oil on each, then spread half of the zucchini pieces on the pan. Give the pieces plenty of room, so that they will sear properly. Put pans back in the oven for 15 minutes, then use a metal spatula to turn the zucchini, sprinkle with the chipotle and salt, then roast for another 10 minutes. The zucchini should be browned, shrunken and very tender.