OK. Here's a start providing a description for São Vicente (one of the Cape Verde islands).
In general for the island, % of time with 11-25 knots is 90-99% November - June with 16-17 knots being most common.
For the 2 main spots (there are at least 3 others):
2 Point breaks that work best with swell coming from Northerly directions (November - March).
Both wil clean waves breaking with wind direction (going out, wind from right). Both very easy waves as at the point they are biggest and going downwind the break gets smaller ending up in a flat water area. If things go wrong here, you drift downwind and end up on a sandy beach (no coral, no stones). A great set-up for non-experts. Wind strenght is as above, side shore.
2 Point breaks that work best when the swell comes from Southerly directions (April - June).
Again, clean waves with cross-offshore wind direction. waves breaking left and right. When going out the wind comes from the left. This spot can be world class. It's considered one of the best spots of the Cape Verde islands and used for the national surfing championships. A cautionary note: the launch and land areas with sand are small (many rocks for the rest of the beach). There are 3 sandy parts, so if you miss one you go to the next and if you miss that one, you'll have to go 500m down the coastline to Tupim beach. The wind here is 1-2 knots weaker (so we normally go here when the wind >17 knots at Salamansa).
Given the rocks and cross-offshore wind this spot is suited only for experts.
How easy is it to get to and from these breaks? is there accommodation nearby? Is it necessary to hire a car? They sound amazing