Slice tomatoes thinly, about 1/8 inch (3 mm) or less. (Retain seeds and liquid to get more flavor, if desired).
Place tomato slices on dehydrator screened trays or on parchment paper.
Place in a dehydrator and dry at 150°F (66°C) or the highest heat temperature because tomato slices should be dry and crispy. Dry for about 3 to 4 hours, then open dehydrator and flip tomatoes over. Continue drying until they are totally dehydrated and crispy.
Pour crispy tomato slices into a blender and process into smooth powder. Store in an air-tight bag or jar.