Do you know how to generate a random number?
You need to use a for each loop to set a variable in each object, then on touching the screen, have Construct generate a random number within the range of the numbers of the objects, and destroy that particular one.
You'll need a variable for the object... for example call it "WhichOne"
You'll need a loop at start of frame for each object, set the number of the object to the loop index of that loop.
You'll then need the on screen touch action in another event.. it should generate a random number from zero to the total number of objects.
Then another loop for each object, if the random number is the same as that variable "which one", then destroy that particular object. and THEN do another loop to re-number them all in their "WhichOne" variable.
Sorry, I don't have time to make an example file.