Melt butter in a skillet over medium heat. Stir cumin and cayenne pepper into the butter until dissolved, about 1 minute. Remove skillet from heat and immediately stir pecans, sucralose sweetener, and salt into the butter mixture to coat the nuts completely. Spread coated nuts onto a baking sheet.
Bake pecans in preheated oven until lightly browned, stirring occasionally, 25 to 30 minutes.