1. Blanch the sweet potato slices in a large saucepan of boiling water for 1 minute. Transfer to paper towels and pat dry. Blanch all the remaining vegetables except the plantain, one vegetable at a time; pat dry. Keep the vegetables separate after blanching.
2. Lightly coat a large microwave-safe plate with cooking spray. Arrange the sweet potato slices, without overlapping, on the plate and season with salt. Microwave on high for 5 minutes. Toss the slices and cook for about 2 more minutes, or until crisp. Spread the chips on a platter to cool, then transfer to a bowl. Repeat with the remaining blanched vegetables, cooking each vegetable separately until the slices stiffen, about 7 minutes per batch. Spray the plate before cooking each batch.
3. Arrange the plantain slices on the sprayed plate and microwave for about 6 minutes, or until beginning to brown. Let cool. If necessary, microwave for 1 to 2 minutes longer, until crisp.
Make Ahead: The chips can be stored in an airtight container for up to 1 week. Recrisp them in a 250° oven.
Notes: ONE CUP: Calories 131 kcal, Protein 2.4 gm, Carbohydrate 32 gm, Cholesterol 0, Total Fat .41 gm, Saturated Fat .1 gm