There are different kinds of offense for beach volleyball. The first and most well-known is the hip or the spike. Another one is the pokey, and there's also something called a roll shot. But when you go out to hit, you're going to hit it with your whole hand as hard as you can, or to place the shot.
When you hit or spike a volleyball, it's important to have a high point of contact. You want to have your arm out in front of you, but as high as possible, to hit over the block or poke deep. When you spike a volleyball, what you're trying to do is put it down onto the sand as fast as possible, before the offense can get there.
When you poke a ball, or the pokey, is when you use the front surface of your knuckles and you poke the ball either short or deep. With a roll shot, it's like a hit. You get tossed in on it, but you don't want to hit it 100% speed, typically 60, 70%. You have more control with this. Some people can also think of offense as how you serve against a team, if you serve extra tough.