Can the server hit the ball before it bounces on the serve in beach tennis?

Yes. The server tosses the ball and hits it directly in the air without letting it bounce. This is standard service procedure in beach tennis. The serve must land in the correct diagonal service box on the other side of the net.

Full Explanation

Per ITF Beach Tennis Rules Rule 7, the server must stand behind the baseline between the center mark and the sideline, toss the ball into the air, and strike it before it touches the ground. The ball may be tossed and let fall without being struck; if this happens, it does not count as a fault but the server must then toss and strike on that same serve attempt. Once the ball is struck by the server, it must travel over the net and land in the correct diagonal service box. The server may use any serve technique (flat, spin, slice) as long as the ball is struck cleanly with one swing. The no-bounce rule (Rule 9.3) applies to play after the serve; the serve itself is an overhead strike from a toss.

Ruleset: ITF  |  Rule Reference: ITF Beach Tennis Rules, Rule 7 (The Service)