Puree cucumbers in a blender.
Drain puree until you have 1/2 - 3/4 c liquid - reserve pulp.
Place liquid in a small saucepan. Sprinkle gelatin lightly over it - allow it to soften for 10 minutes. Heat, over a low heat, stirring, until gelatin melts completely. Set aside to cool 5 minutes.
Return gel mixture and pulp to blender - pulse 2-3 times to mix completely. Pour into a work bowl and chill half an hour to thicken.
Chop salad vegetables finely.
Stir chopped vegetables into cucumber gelatin mixture, stirring well to suspend the vegetables. Turn into serving bowl.
Chill 4 hours or more before serving.