Best ways to meet Tunisians and have conversations with locals are:

• Public Transportation: this is one of the best ways to start up a conversation with a Tunisian. Tunisians are very curious, and love to talk, so don't be afraid to start up a convo!
• Hitch-hiking: if you are brave-enough to hitch a ride, this is a great way to meet locals. Mostly in the country-side, you'll be able to find a friendly Tunisian who'll be glad to pick you up. You may even end up being invited to their home for dinner and tea.
• Local cafe: A predominantly male-domain, this is a good way for men to meet other Tunisians.
• Parties and Marriages: Many times parties and marriages are held in public places, and tourists are always welcome to enter and watch. Be sure to congratulate the newly-weds and compliment the women on her beauty.