Sprinkle tomatoes with salt; let stand 15 minutes. Drain tomatoes on paper towels and pat dry., Grill peaches on an oiled grill rack, covered, over medium heat or broil 4 in. from heat until peaches have grill marks and are tender, 2-3 minutes on each side, turning once. Remove peaches; cool slightly. Cut into slices., Coat a 15x10x1-in. baking pan with cooking spray; sprinkle with cornmeal. Unroll crust into pan, pressing into a 12x10-in. rectangle. Spritz with cooking spray. Invert crust onto grill. Grill, covered, over medium heat until bottom is lightly browned, 2-3 minutes. Remove from grill, inverting onto baking pan., Layer grilled side of pizza with tomatoes, peaches and cheese. Return pizza to grill. Cook, covered, until crust is lightly browned and cheese is melted, 3-4 minutes, rotating halfway through cooking to ensure an evenly browned crust. Sprinkle with basil and pepper.