Preheat oven to 450°F. Line bottom crust with raw rice or dry beans to weigh the crust down. Bake for 8 min, remove, let cool slightly.
Reduce temperature to 350°F. Layer tomatoes, herbs, onions and cheese evenly in bottom pie shell. In med bowl, mix mayonnaise, lemon juice, salt and pepper, spread over tomato mix evenly. Place second crust over top, crimp edges to seal. Using a sharp paring knife, cut 4 steam vents on top.
Bake until crust is golden and filling is bubbly, for 45-50 min. Let stand for 15 min before slicing.