I'd suggest a 25m and a 35m on 50m lines - wind is typically very light. I have family there and have been visiting regulary for the last 10 years, only ever had 3 windy days
Unless there is a very good forecast don't even bother going down the beach until the after noon, what wind they do have is sea breeze whick will kick in quite regulary around 13:00/14:00 but it's normally only about 8 -12 knots which is ok for the light weights on surfboards but no good for heavy guys, I'm 90kg.
During the summer you can't kite on the busy beaches, Santa Pola main beach is a no go but there is a designated kitespot at the south end of the sea front near the big salt mountains but it's not a great place to surf, just a small crappy beach with a school & arsey instructors at one end and swimming zones at the other. La Marina town (not the urbinization) is probably the best spot about half hour from Alicante, again designated kitezone but it can get busy and people sit right in the launch zone, they have restaurants, beach bars, showers etc there so nice place to visit - go through the town and you'll come to a junction with a big shop selling concrete statues and pottery etc, just head down the road opposite towards the beach