Scoop flesh from avocado halves into bowl. Mash coarsely with fork. Stir in onion, lime juice, garlic powder, salt and pepper, mashing to desired consistency. Cover with plastic wrap; refrigerate until serving time.
Heat oven to very low (180°F). Place corn kernels in food processor. Pulse until coarsely chopped and slightly wet. Add buttermilk, eggs and oil. Pulse just until blended.
In large bowl, whisk together flour, cornmeal, salt, baking powder and cumin. Stir in grated cheese. Stir corn mixture into flour mixture.
Heat griddle or large nonstick skillet over medium heat. Coat griddle with nonstick cooking spray.
For each pancake, spoon 2 tablespoons of batter onto heated pan; gently spread batter slightly to form 3-1/2-inch circles. Cook until bubbles begin to appear on top of pancakes, 1 to 2 minutes. Flip pancakes over with large spatula; cook 1 to 2 minutes. Keep pancakes warm in 180°F oven. You should have about 24 pancakes.
To serve, top each pancake with 1 tablespoon guacamole and 1 teaspoon chopped tomatoes. Garnish with cilantro, if desired.