The motion of a Wave Energy Converter (WEC) can be described in terms of an integro-differential equation, which includes a convolution term accounting for the radiation forces. Since such a convolution term represents a drawback for both simulation and model-based control, it is usually approximated by a parametric form to be later embedded into the WEC dynamical equation. When an array of WECs is considered, a separate convolution term is required for each cross-coupling component (arising from device interactions), which increases the complexity of the problem. In this paper, a framework to compute a parametric model for array of WEC devices based on moment-matching is presented. The proposed method shows a significant simulation computational saving, compared to other parametric identification methods, which is illustrated by the means of a numerical example.