Preheat the oven to 350°F. Lightly grease (or line with parchment) two baking sheets. In a large bowl, combine the sugars, butter, salt, vanilla extract, and baking soda, beat until smooth and creamy.
Add the egg, again beating until smooth. Scrape the bottom and sides of the bowl with a spatula to make sure everything is thoroughly combined. Mix in the whole rye flour, then the chocolate chips.
Use a spoon to scoop 1 1/4" balls of dough onto the baking sheets, leaving space between them on all sides; they'll spread as they bake. Bake the cookies for 15 to 20 minutes, until their edges are chestnut brown and their tops are light golden brown, almost blonde.
Remove the cookies from the oven, cool on the pan until they've set enough to move without breaking. Repeat with the remaining dough. Store cookies, well wrapped, at room temperature for several days; freeze for longer storage.