Heat a medium skillet over medium heat. Add extra-virgin olive oil, garlic, anchovy paste and red pepper flakes. When anchovies (if whole) melt or garlic is tender, about 2 minutes, add tomatoes and olives. Simmer sauce 3 to 4 minutes. Top the pizza with sauce and the sliced cheese. Bake until pizza until cheese melts and crust is crisp, 10 minutes. Cut and serve.