Melt 2 Tbs. of the butter in an 8-inch skillet over medium-low heat. Whisk in the apricot jam and the chili garlic sauce, mashing the larger pieces of fruit with the back of a spoon, until the jam is melted. Set aside off the heat.
Pat the fish dry, season the flesh side of each fillet with a large pinch each of salt and pepper, and spread each fillet with 1 Tbs. of the glaze, using the back of the spoon (leave any remaining glaze in the pan).
Melt 1 Tbs. of the butter with 1 Tbs. of the sesame oil in a 12-inch nonstick skillet over medium-high heat. Add the fish, glazed side down, and cook for 2 minutes. Using a large spatula, flip the fillets and cook until opaque in the center and just firm to the touch, about 3 minutes. Transfer the fish to 4 dinner plates.
Melt the remaining 1 Tbs. butter with the remaining 1 Tbs. sesame oil in a wide heavy-duty 5- to 6 quart pot over high heat. Add the garlic and stir until fragrant, about 30 seconds. Add the spinach, sprinkle with the soy sauce, 1/2 tsp. salt, and 1/2 tsp. pepper and then toss until the spinach is just wilted but not yet releasing water, about 2 minutes. Remove from the heat. Divide the spinach among the plates.
Heat the remaining glaze over low heat if very thick, and drizzle over the catfish. Sprinkle with the sesame seeds and serve.