Mix together sugar and salt. Puree onions, carrots, peppers, lemons, and limes together in a food processor. Combine sugar mixture and puree. Add tequila. Pour half of the mixture into the bottom of a large pan. Coat flesh side of salmon with pepper. Place salmon in the pan (skin side up). Cover salmon with remaining mixture and place another pan on top with plenty of weight. Refrigerate for 2 days.
To serve, slice thinly and place on top of sweet corn cakes, Cachapas or Cuban crackers.
Serving suggestion: sweet corn cakes (cachapas) or Cuban crackers.