Preheat your oven to 350°F (180°C).
Spread the sesame seeds in a single layer on a baking sheet.
Toast the seeds in the oven for 8-10 minutes, stirring occasionally, until golden brown. Be careful not to burn them.
Let the seeds cool for a few minutes, then transfer them to a food processor or blender.
Add the olive oil to the processor/blender, starting with 1/4 cup, and blend the mixture until smooth.
If the tahini is too thick, add more olive oil gradually until you reach the desired consistency.
Taste the tahini and add salt, if desired.