Prepare the gelatin by dissolving the leaves in water. Sauté the peas in a pan with oil and salt. In a small, round baking form, arrange the liquid gelatin, diced cooked ham, peas and mayonnaise. Alternate the layers to create fun different shapes. To make sure that the end result is appealing, place in the freezer for a few minutes between each layer, ensuring that the gelatin sets slightly and that the position of the second layer remains properly separated. Once the mould has been filled, let rest in the freezer until fully set. Remove from the form by turning it upside-down on a plate. Serve with slices of cooked ham.