In a large bowl, toss together the carrots, kohlrabi, Fresno peppers and onions. Refrigerate until ready to serve.
In a separate bowl, whisk together the lime juice, fish sauce, brown sugar, vinegar, chili-garlic sauce and minced garlic. Set aside until ready to serve.
Heat the peanut oil in a medium skillet over medium-high heat. Add the sliced Chinese sausage. When the sausage is golden brown on both sides, about 4 minutes, remove the slices to a paper-towel-lined plate. Turn the heat down to low and add the sliced garlic to the pan. Stir periodically until the garlic turns golden brown, about 5 minutes. Reserve the oil. Take off the heat and cool.
Just before you're ready to serve the slaw, add the dressing, sausage, sliced garlic, reserved garlic oil, peanuts and mint to the bowl of cut vegetables. Toss and serve.
This salad tastes best when freshly assembled. Make sure to keep the dressing separate from the vegetables until you are ready to serve the salad.