Smoked Salmon, Tomato and Feta Pizza without pasta

150 g cherry tomatoes 1 small red onion 1 small avocado (ripe) 1 lemon, juice of (reserve 1 tsp for later use) 2 tablespoons creme fraiche (may sub sour[...]

2 whole wheat pita bread rounds, carefully torn in half as to have four thin rounds 2 teaspoons lemon zest , lemon 1 small red onion , thinly sliced 1/2 cup[...]