I make a really simple Clam Pizza that has become the favorite of my family, and proceed as follows:
1. Shuck fresh clams (smaller clams tend to be more tender, and this is what I try and use), reserving the clam juice.
2. Strain clam juice and add a few tablespoons of olive oil (measurements are not really that important, in my experience, but I would guess there are two parts clam juice to one part oil).
3. Slice garlic into thin slices and add to oil/juice mix.
4. Put clams on pizza (I do not chop them), followed by the oil/juice/garlic mix. If you like spicey food, sprinkle red pepper flakes on pizza as well. I then grate some grana padana or parmesian-reggiano over the pizza.
5. You need to work pretty fast after step 4 to get the pizza in the oven, as the oil/juice mix is pretty wet, and you do not want it to make your dough soggy.
There are probably many variations on this simple theme, but the taste of this pizza is pure, simple and delicious. Good luck.