Preheat oven to 190°C (375°F). Line 2 or 3 baking sheets with parchment paper. In bowl, whisk together flour, baking soda and salt; set aside.
In separate bowl, using electric mixer, beat together butter, tahini and both kinds of sugar until light and fluffy, about 2 min. Beat in egg and vanilla. Use a spatula to stir in flour mixture until just incorporated. Fold in oats and chocolate chips.
Drop dough, by heaping tablespoonfuls, about 2-in. (5-cm) apart, onto lined baking sheets. Bake, in batches, 8 min, or until tops are set and cookies are golden around edges. Cool on baking sheet 5 min.; transfer to wire rack to cool completely. Store in airtight container for up to 1 week.
Substitute chopped dates for chocolate.