What challenging questions can I ask my opponent, who is for raising the minimum wage? This is for a debate?

"How can small businesses keep afloat if the cost of doing business increases?"

"If you argue that people are making more money, what prevents business owners from charging more for a good so they can make money of their own?"

~Aizen

If you are worth $2, why should I be forced to pay you anything other than $2? Why hire you at all if the government is going to interfere with wages and prices? Why not just outsource overseas?

go for ad hominem