labels say to refrigerate tahini after opening. This way it goes rancid only after 3+ months. Olive oil would dillute the taste, so if your tahini is thin, it would dillute it even more.
Use in recipes
* Add to stir-fry at the end as a thickener and instead of sesame oil.
* Warm it up over low heat with brown sugar/honey and sprinkle with lemon juice after - traditional Turkish dessert. Can also add ice cream after. If you can get some of the oil out the paste before warming it up, it would keep its form better.
* Dipping sauce for veggies, chicken, etc - add some spicy ingredient, like chili or tobasco, roasted garlic, some herb, lemon juice, a bit of sugar/mollases, possibly dillute with some other base, and done.
* Saute greens, like kale, spinach, etc with onion and garlic, and at the end add tahini with lemon juice.
If interested, lmk and I'll see if I can dig up some Turkish recipes