Trim the stem end off of the zucchini. Using a mandoline, thinly shave the zucchini from pole to pole into beautiful long ribbons.
In a small bowl, whisk together the lime juice, chile, brown sugar, fish sauce and garlic.
Set a small skillet over high heat. Add the peanuts and toast until they begin to char, about 5 minutes. Remove them from the heat, and finely chop.
Toss the zucchini with the dressing, tomatoes and cilantro. Sprinkle with the peanuts. Taste for seasoning (it may need a touch more salt) and serve immediately.