[betgo]

I would call the overbet. It is dangerous in general to call this type of raise, but it is not easy to see how you could be beaten. If your opponent had aces, kings, or queens he probably would have reraised preflop. The only other hands you are worried about are sets of 7s or 3s or 2 pair. He would have to have a pretty bad starting hand to have 2 pair, but since he called a miniraise in the BB, it is possible.

If he has a big hand, you have to wonder why he doesn't play it slower, but he could be a bad player or he may think you did hit something and will call. If he somehow had 2 pairs 7s and 3s, he might think you have a queen or a pocket pair and does not want to be drawn out on.

The most likely thing is that he has either a heart draw or a queen. With a queen, he might think he is ahead and wants to win the pot now, figuring you have at least one overcard.

He could have a pp, a 7 or 3, or be on a bluff, and he might figure you missed the flop but would bet anyway as the preflop raiser.

I would definately not fold preflop, particularly in a $2 tournament. A larger raise is more standard, particularly for this kind of hand, but since you are UTG a miniraise is OK. You could also limp, and decide whether to fold, call, or reraise if you are raised, depending on the situation.