Preset the oven to 350 degrees F. Cut rhubarb into 1/4 inch slices and combine with sugar, zest and lime juice in a bowl, stirring until the rhubarb starts to produce juice. Spread in the bottom of an appropriate sized glass baking dish (I used 7 1/2 x 11). Mix the flour, sugar, baking soda, salt and cinnamon. Add the margarine, using a fork to mix, until mixed and it looks like crumbs. Sprinkle over the rhubarb in desired thickness. The crumb mixture makes a generous amount, extra can be used for a second crisp. Bake uncovered for 45-60 minutes, periodically checking for browning. Depending on the amount of time the rhubarb sets before baking and the amount of stirring done, the dish will have a fair amount of liquid, which will bubble as it cooks. When you check for browning, make sure it isn't at risk for bubbling over. When the edges are browned, it is finished. After the first piece was out, I spoon out a lot of the excess liquid and save for an ice cream syrup or to add as the sugar in smoothies. This is excellent warm on ice cream!