Blend or process 2 tablespoons of the oil, paste, garlic, rind, juice, chilli, paprika and oregano until smooth. Season to taste.
Rinse chicken under cold water; pat dry inside and out with absorbent paper. Place lemon quarters and thyme inside cavity of chicken; secure cavity with a fine skewer.
Make a pocket under skin of breast, drumsticks and thighs with fingers. Using disposable gloves, rub ¼ cup of paste under skin. Tuck wing tips under chicken; tie legs together with kitchen string. Rub ¼ cup of paste all over chicken.
Heat remaining oil in large frying pan; cook chicken until browned all over. Transfer to 4.5-litre (18-cup) slow cooker. Cook, covered, on low, 6 hours.
Cut chicken into pieces; accompany with the remaining paste