Add boneless skinless chicken thighs, soy sauce, dark soy sauce, honey, mirin, ginger paste, and garlic paste to slow cooker
Cook on High for 4-5 hours OR on Low for 5+ hours
Mix cornstarch and cold water in a small bowl to create slurry
Add cornstarch slurry to slow cooker after chicken is done and let sit uncovered for 15-20 minutes to thicken sauce
Cook short grain or sushi rice according to package directions
Prepare Low-Cal Yum Yum Sauce by mixing low-fat mayo, greek yogurt, sriracha, salt, pepper, and garlic powder, adjusting milk for desired consistency
Serve teriyaki chicken over rice, garnish with chopped green onions, and serve with yum yum sauce on the side