Heat the oven to 350°F with a rack in the lower-middle position. Grease a 9-inch springform pan, line the bottom with parchment, wrap the outside bottom with foil and set it on a rimmed sheet pan.
Combine graham crumbs, 2 tablespoons sugar and 1/4 teaspoon salt. Mix in melted butter, press evenly over the pan bottom and bake 8 minutes. Cool at least 10 minutes and reduce the oven to 325°F.
Beat softened cream cheese on low for about 60 seconds, scraping thoroughly. Add 3/4 cup sugar and cornstarch and mix on low until creamy.
Add Greek yogurt in three portions, mixing on low and scraping after each. Mix in vanilla, lemon zest, lemon juice and 1/4 teaspoon salt until smooth.
Add eggs one at a time on the lowest speed, stopping as soon as each disappears. Scrape once and fold by hand several times; do not whip.
Pour batter over the cooled crust, smooth the top and tap the pan gently two or three times. Pop only the largest surface bubbles.
Bake at 325°F for 50 to 65 minutes, until the outer 2 inches are set and a 2- to 3-inch center circle moves as one soft unit when nudged.
Turn off the oven, crack the door and leave the cheesecake inside 30 minutes. Cool on a rack about 1 hour, running a thin knife around the edge after the first 15 minutes.
Cover and refrigerate at least 6 hours, preferably overnight. Remove the springform ring only when fully cold.
Warm a thin sharp knife in hot water, wipe dry and cut. Clean and warm the blade between slices; let slices stand 10 to 15 minutes before serving.
